{ "language": "Solidity", "sources": { "contracts/handlers/ERC721Handler.sol": { "content": "// SPDX-License-Identifier: LGPL-3.0-only\npragma solidity ^0.8.0;\n\nimport \"@openzeppelin/contracts/utils/introspection/ERC165Checker.sol\";\nimport \"@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol\";\nimport \"../interfaces/IDepositExecute.sol\";\nimport \"./HandlerHelpers.sol\";\nimport \"./ERC721Safe.sol\";\n\n/// @notice This contract is intended to be used with the Bridge contract.\n\ncontract ERC721Handler is IDepositExecute, HandlerHelpers, ERC721Safe {\n using ERC165Checker for address;\n\n bytes4 private constant _INTERFACE_ERC721_METADATA = 0x5b5e139f;\n\n /// @param bridgeAddress Contract address of previously deployed Bridge.\n constructor(address bridgeAddress) HandlerHelpers(bridgeAddress) {}\n\n /// @notice A deposit is initiatied by making a deposit in the Bridge contract.\n ///\n /// @notice Requirements:\n /// - It must be called by only bridge.\n /// - {tokenAddress} must be whiltelisted.\n ///\n /// @param resourceID ResourceID used to find address of token to be used for deposit.\n /// @param depositer Address of account making the deposit in the Bridge contract.\n /// @param data Consists of {tokenID} padded to 32 bytes.\n /// @return metaData : the deposited token metadata acquired by calling a {tokenURI} method in the token contract.\n ///\n /// @notice Data passed into the function should be constructed as follows:\n /// tokenID uint256 bytes 0 - 32\n ///\n /// @notice If the corresponding {tokenAddress} for the parsed {resourceID} supports {_INTERFACE_ERC721_METADATA},\n /// then {metaData} will be set according to the {tokenURI} method in the token contract.\n ///\n /// @dev Depending if the corresponding {tokenAddress} for the parsed {resourceID} is\n /// marked true in {_burnList}, deposited tokens will be burned, if not, they will be locked.\n // slither-disable-next-line locked-ether\n function deposit(\n bytes32 resourceID,\n address depositer,\n bytes calldata data\n ) external payable override onlyBridge returns (bytes memory metaData) {\n require(msg.value == 0, \"can't accept value\");\n uint256 tokenID;\n\n (tokenID) = abi.decode(data, (uint256));\n\n address tokenAddress = _resourceIDToTokenContractAddress[resourceID];\n require(\n _contractWhitelist[tokenAddress],\n \"not an allowed token address\"\n );\n\n // Check if the contract supports metadata, fetch it if it does\n if (tokenAddress.supportsInterface(_INTERFACE_ERC721_METADATA)) {\n IERC721Metadata erc721 = IERC721Metadata(tokenAddress);\n metaData = bytes(erc721.tokenURI(tokenID));\n }\n\n if (_burnList[tokenAddress]) {\n burnERC721(tokenAddress, depositer, tokenID);\n } else {\n lockERC721(tokenAddress, depositer, address(this), tokenID);\n }\n }\n\n /// @notice Proposal execution should be initiated when a proposal is finalized in the Bridge contract.\n /// by a relayer on the deposit's destination chain.\n ///\n /// @notice Requirements:\n /// - It must be called by only bridge.\n /// - {tokenAddress} must be whiltelisted.\n ///\n /// @param data Consists of {tokenID}, {resourceID}, {lenDestinationRecipientAddress},\n /// {destinationRecipientAddress}, {lenMeta}, and {metaData} all padded to 32 bytes.\n ///\n /// @notice Data passed into the function should be constructed as follows:\n /// tokenID uint256 bytes 0 - 32\n /// destinationRecipientAddress length uint256 bytes 32 - 64\n /// destinationRecipientAddress bytes bytes 64 - (64 + len(destinationRecipientAddress))\n /// metadata length uint256 bytes (64 + len(destinationRecipientAddress)) - (64 + len(destinationRecipientAddress) + 32)\n /// metadata bytes bytes (64 + len(destinationRecipientAddress) + 32) - END\n function executeProposal(bytes32 resourceID, bytes calldata data)\n external\n override\n onlyBridge\n {\n uint256 tokenID;\n uint256 lenDestinationRecipientAddress;\n bytes memory destinationRecipientAddress;\n uint256 offsetMetaData;\n uint256 lenMetaData;\n bytes memory metaData;\n\n (tokenID, lenDestinationRecipientAddress) = abi.decode(\n data,\n (uint256, uint256)\n );\n offsetMetaData = 64 + lenDestinationRecipientAddress;\n destinationRecipientAddress = bytes(data[64:offsetMetaData]);\n lenMetaData = abi.decode(data[offsetMetaData:], (uint256));\n metaData = bytes(\n data[offsetMetaData + 32:offsetMetaData + 32 + lenMetaData]\n );\n\n bytes20 recipientAddress;\n\n // slither-disable-next-line assembly\n assembly {\n // Skip the length field (first 32 bytes) and load 32 bytes\n recipientAddress := mload(add(destinationRecipientAddress, 0x20))\n }\n\n address tokenAddress = _resourceIDToTokenContractAddress[resourceID];\n require(\n _contractWhitelist[address(tokenAddress)],\n \"not an allowed token address\"\n );\n\n if (_burnList[tokenAddress]) {\n mintERC721(\n tokenAddress,\n address(recipientAddress),\n tokenID,\n metaData\n );\n } else {\n releaseERC721(\n tokenAddress,\n address(this),\n address(recipientAddress),\n tokenID\n );\n }\n }\n\n /// @notice Used to manually release ERC721 tokens from ERC721Safe.\n ///\n /// @notice Requirements:\n /// - It must be called by only bridge.\n ///\n /// @param data Consists of {tokenAddress}, {recipient}, and {tokenID} all padded to 32 bytes.\n ///\n /// @notice Data passed into the function should be constructed as follows:\n /// tokenAddress address bytes 0 - 32\n /// recipient address bytes 32 - 64\n /// tokenID uint bytes 64 - 96\n function withdraw(bytes memory data) external override onlyBridge {\n address tokenAddress;\n address recipient;\n uint256 tokenID;\n\n (tokenAddress, recipient, tokenID) = abi.decode(\n data,\n (address, address, uint256)\n );\n\n releaseERC721(tokenAddress, address(this), recipient, tokenID);\n }\n}\n" }, "@openzeppelin/contracts/utils/introspection/ERC165Checker.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165Checker.sol)\n\npragma solidity ^0.8.0;\n\nimport \"./IERC165.sol\";\n\n/**\n * @dev Library used to query support of an interface declared via {IERC165}.\n *\n * Note that these functions return the actual result of the query: they do not\n * `revert` if an interface is not supported. It is up to the caller to decide\n * what to do in these cases.\n */\nlibrary ERC165Checker {\n // As per the EIP-165 spec, no interface should ever match 0xffffffff\n bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;\n\n /**\n * @dev Returns true if `account` supports the {IERC165} interface,\n */\n function supportsERC165(address account) internal view returns (bool) {\n // Any contract that implements ERC165 must explicitly indicate support of\n // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid\n return\n _supportsERC165Interface(account, type(IERC165).interfaceId) &&\n !_supportsERC165Interface(account, _INTERFACE_ID_INVALID);\n }\n\n /**\n * @dev Returns true if `account` supports the interface defined by\n * `interfaceId`. Support for {IERC165} itself is queried automatically.\n *\n * See {IERC165-supportsInterface}.\n */\n function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {\n // query support of both ERC165 as per the spec and support of _interfaceId\n return supportsERC165(account) && _supportsERC165Interface(account, interfaceId);\n }\n\n /**\n * @dev Returns a boolean array where each value corresponds to the\n * interfaces passed in and whether they're supported or not. This allows\n * you to batch check interfaces for a contract where your expectation\n * is that some interfaces may not be supported.\n *\n * See {IERC165-supportsInterface}.\n *\n * _Available since v3.4._\n */\n function getSupportedInterfaces(address account, bytes4[] memory interfaceIds)\n internal\n view\n returns (bool[] memory)\n {\n // an array of booleans corresponding to interfaceIds and whether they're supported or not\n bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length);\n\n // query support of ERC165 itself\n if (supportsERC165(account)) {\n // query support of each interface in interfaceIds\n for (uint256 i = 0; i < interfaceIds.length; i++) {\n interfaceIdsSupported[i] = _supportsERC165Interface(account, interfaceIds[i]);\n }\n }\n\n return interfaceIdsSupported;\n }\n\n /**\n * @dev Returns true if `account` supports all the interfaces defined in\n * `interfaceIds`. Support for {IERC165} itself is queried automatically.\n *\n * Batch-querying can lead to gas savings by skipping repeated checks for\n * {IERC165} support.\n *\n * See {IERC165-supportsInterface}.\n */\n function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {\n // query support of ERC165 itself\n if (!supportsERC165(account)) {\n return false;\n }\n\n // query support of each interface in _interfaceIds\n for (uint256 i = 0; i < interfaceIds.length; i++) {\n if (!_supportsERC165Interface(account, interfaceIds[i])) {\n return false;\n }\n }\n\n // all interfaces supported\n return true;\n }\n\n /**\n * @notice Query if a contract implements an interface, does not check ERC165 support\n * @param account The address of the contract to query for support of an interface\n * @param interfaceId The interface identifier, as specified in ERC-165\n * @return true if the contract at account indicates support of the interface with\n * identifier interfaceId, false otherwise\n * @dev Assumes that account contains a contract that supports ERC165, otherwise\n * the behavior of this method is undefined. This precondition can be checked\n * with {supportsERC165}.\n * Interface identification is specified in ERC-165.\n */\n function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {\n bytes memory encodedParams = abi.encodeWithSelector(IERC165.supportsInterface.selector, interfaceId);\n (bool success, bytes memory result) = account.staticcall{gas: 30000}(encodedParams);\n if (result.length < 32) return false;\n return success && abi.decode(result, (bool));\n }\n}\n" }, "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional metadata extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Metadata is IERC721 {\n /**\n * @dev Returns the token collection name.\n */\n function name() external view returns (string memory);\n\n /**\n * @dev Returns the token collection symbol.\n */\n function symbol() external view returns (string memory);\n\n /**\n * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.\n */\n function tokenURI(uint256 tokenId) external view returns (string memory);\n}\n" }, "contracts/interfaces/IDepositExecute.sol": { "content": "// SPDX-License-Identifier: LGPL-3.0-only\npragma solidity ^0.8.0;\n\ninterface IDepositExecute {\n /// @notice It is intended that deposit are made using the Bridge contract.\n /// @param resourceID ResourceID to be used.\n /// @param depositer Address of account making the deposit in the Bridge contract.\n /// @param data Consists of additional data needed for a specific deposit.\n function deposit(\n bytes32 resourceID,\n address depositer,\n bytes calldata data\n ) external payable returns (bytes memory);\n\n /// @notice It is intended that proposals are executed by the Bridge contract.\n /// @param resourceID ResourceID to be used.\n /// @param data Consists of additional data needed for a specific deposit execution.\n function executeProposal(bytes32 resourceID, bytes calldata data) external;\n}\n" }, "contracts/handlers/HandlerHelpers.sol": { "content": "// SPDX-License-Identifier: LGPL-3.0-only\npragma solidity ^0.8.0;\n\nimport \"../interfaces/IERCHandler.sol\";\n\n/// @notice This contract is intended to be used with the Bridge contract.\n\ncontract HandlerHelpers is IERCHandler {\n address public immutable _bridgeAddress;\n\n // resourceID => token contract address\n mapping(bytes32 => address) public _resourceIDToTokenContractAddress;\n\n // token contract address => resourceID\n mapping(address => bytes32) public _tokenContractAddressToResourceID;\n\n // token contract address => is whitelisted\n mapping(address => bool) public _contractWhitelist;\n\n // token contract address => is burnable\n mapping(address => bool) public _burnList;\n\n modifier onlyBridge() {\n _onlyBridge();\n _;\n }\n\n /// @param bridgeAddress Contract address of previously deployed Bridge.\n constructor(address bridgeAddress) {\n _bridgeAddress = bridgeAddress;\n }\n\n function _onlyBridge() private view {\n require(msg.sender == _bridgeAddress, \"sender must be bridge contract\");\n }\n\n /// @notice First verifies {_resourceIDToContractAddress}[{resourceID}] and\n /// {_contractAddressToResourceID}[{contractAddress}] are not already set,\n /// then sets {_resourceIDToContractAddress} with {contractAddress},\n /// {_contractAddressToResourceID} with {resourceID},\n /// and {_contractWhitelist} to true for {contractAddress}.\n ///\n /// @param resourceID ResourceID to be used when making deposits.\n /// @param contractAddress Address of contract to be called when a deposit is made and a deposited is executed.\n function setResource(bytes32 resourceID, address contractAddress)\n external\n override\n onlyBridge\n {\n _setResource(resourceID, contractAddress);\n }\n\n /// @notice First verifies {contractAddress} is whitelisted, then sets {_burnList}[{contractAddress}]\n /// to true.\n ///\n /// @param contractAddress Address of contract to be used when making or executing deposits.\n function setBurnable(address contractAddress) external override onlyBridge {\n _setBurnable(contractAddress);\n }\n\n function withdraw(bytes memory data) external virtual override {}\n\n function _setResource(bytes32 resourceID, address contractAddress)\n internal\n {\n _resourceIDToTokenContractAddress[resourceID] = contractAddress;\n _tokenContractAddressToResourceID[contractAddress] = resourceID;\n\n _contractWhitelist[contractAddress] = true;\n }\n\n function _setBurnable(address contractAddress) internal {\n require(\n _contractWhitelist[contractAddress],\n \"not an allowed token address\"\n );\n _burnList[contractAddress] = true;\n }\n}\n" }, "contracts/handlers/ERC721Safe.sol": { "content": "// SPDX-License-Identifier: LGPL-3.0-only\npragma solidity ^0.8.0;\n\nimport \"@openzeppelin/contracts/token/ERC721/IERC721.sol\";\nimport \"@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol\";\nimport \"../interfaces/IMint.sol\";\n\n/// @notice This contract is intended to be used with ERC721Handler contract.\n\ncontract ERC721Safe {\n /// @notice Used to gain custoday of deposited token.\n ///\n /// @param tokenAddress Address of ERC721 to transfer.\n /// @param owner Address of current token owner.\n /// @param recipient Address to transfer token to.\n /// @param tokenID ID of token to transfer.\n function lockERC721(\n address tokenAddress,\n address owner,\n address recipient,\n uint256 tokenID\n ) internal {\n IERC721 erc721 = IERC721(tokenAddress);\n erc721.transferFrom(owner, recipient, tokenID);\n }\n\n /// @notice Transfers custody of token to recipient.\n ///\n /// @param tokenAddress Address of ERC721 to transfer.\n /// @param owner Address of current token owner.\n /// @param recipient Address to transfer token to.\n /// @param tokenID ID of token to transfer.\n // slither-disable-next-line calls-loop\n function releaseERC721(\n address tokenAddress,\n address owner,\n address recipient,\n uint256 tokenID\n ) internal {\n IERC721 erc721 = IERC721(tokenAddress);\n erc721.transferFrom(owner, recipient, tokenID);\n }\n\n /// @notice Used to create new ERC721s.\n ///\n /// @param tokenAddress Address of ERC721 to mint.\n /// @param recipient Address to mint token to.\n /// @param tokenID ID of token to mint.\n /// @param data Optional data to send along with mint call.\n // slither-disable-next-line calls-loop\n function mintERC721(\n address tokenAddress,\n address recipient,\n uint256 tokenID,\n bytes memory data\n ) internal {\n IMint erc721 = IMint(tokenAddress);\n erc721.mint(recipient, tokenID, string(data));\n }\n\n /// @notice Used to burn ERC721s.\n ///\n /// @param tokenAddress Address of ERC721 to burn.\n /// @param tokenID ID of token to burn.\n function burnERC721(\n address tokenAddress,\n address owner,\n uint256 tokenID\n ) internal {\n ERC721Burnable erc721 = ERC721Burnable(tokenAddress);\n require(erc721.ownerOf(tokenID) == owner, \"not the owner\");\n erc721.burn(tokenID);\n }\n}\n" }, "@openzeppelin/contracts/utils/introspection/IERC165.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC165 standard, as defined in the\n * https://eips.ethereum.org/EIPS/eip-165[EIP].\n *\n * Implementers can declare support of contract interfaces, which can then be\n * queried by others ({ERC165Checker}).\n *\n * For an implementation, see {ERC165}.\n */\ninterface IERC165 {\n /**\n * @dev Returns true if this contract implements the interface defined by\n * `interfaceId`. See the corresponding\n * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]\n * to learn more about how these ids are created.\n *\n * This function call must use less than 30 000 gas.\n */\n function supportsInterface(bytes4 interfaceId) external view returns (bool);\n}\n" }, "@openzeppelin/contracts/token/ERC721/IERC721.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../../utils/introspection/IERC165.sol\";\n\n/**\n * @dev Required interface of an ERC721 compliant contract.\n */\ninterface IERC721 is IERC165 {\n /**\n * @dev Emitted when `tokenId` token is transferred from `from` to `to`.\n */\n event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);\n\n /**\n * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.\n */\n event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);\n\n /**\n * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.\n */\n event ApprovalForAll(address indexed owner, address indexed operator, bool approved);\n\n /**\n * @dev Returns the number of tokens in ``owner``'s account.\n */\n function balanceOf(address owner) external view returns (uint256 balance);\n\n /**\n * @dev Returns the owner of the `tokenId` token.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function ownerOf(uint256 tokenId) external view returns (address owner);\n\n /**\n * @dev Safely transfers `tokenId` token from `from` to `to`.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must exist and be owned by `from`.\n * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function safeTransferFrom(\n address from,\n address to,\n uint256 tokenId,\n bytes calldata data\n ) external;\n\n /**\n * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must exist and be owned by `from`.\n * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function safeTransferFrom(\n address from,\n address to,\n uint256 tokenId\n ) external;\n\n /**\n * @dev Transfers `tokenId` token from `from` to `to`.\n *\n * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must be owned by `from`.\n * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n *\n * Emits a {Transfer} event.\n */\n function transferFrom(\n address from,\n address to,\n uint256 tokenId\n ) external;\n\n /**\n * @dev Gives permission to `to` to transfer `tokenId` token to another account.\n * The approval is cleared when the token is transferred.\n *\n * Only a single account can be approved at a time, so approving the zero address clears previous approvals.\n *\n * Requirements:\n *\n * - The caller must own the token or be an approved operator.\n * - `tokenId` must exist.\n *\n * Emits an {Approval} event.\n */\n function approve(address to, uint256 tokenId) external;\n\n /**\n * @dev Approve or remove `operator` as an operator for the caller.\n * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.\n *\n * Requirements:\n *\n * - The `operator` cannot be the caller.\n *\n * Emits an {ApprovalForAll} event.\n */\n function setApprovalForAll(address operator, bool _approved) external;\n\n /**\n * @dev Returns the account approved for `tokenId` token.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function getApproved(uint256 tokenId) external view returns (address operator);\n\n /**\n * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.\n *\n * See {setApprovalForAll}\n */\n function isApprovedForAll(address owner, address operator) external view returns (bool);\n}\n" }, "contracts/interfaces/IERCHandler.sol": { "content": "// SPDX-License-Identifier: LGPL-3.0-only\npragma solidity ^0.8.0;\n\ninterface IERCHandler {\n /// @notice Correlates {resourceID} with {contractAddress}.\n /// @param resourceID ResourceID to be used when making deposits.\n /// @param contractAddress Address of contract to be called when a deposit is made and a deposited is executed.\n function setResource(bytes32 resourceID, address contractAddress) external;\n\n /// @notice Marks {contractAddress} as mintable/burnable.\n /// @param contractAddress Address of contract to be used when making or executing deposits.\n function setBurnable(address contractAddress) external;\n\n /// @notice Withdraw funds from ERC safes.\n /// @param data ABI-encoded withdrawal params relevant to the handler.\n function withdraw(bytes memory data) external;\n}\n" }, "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/extensions/ERC721Burnable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../ERC721.sol\";\nimport \"../../../utils/Context.sol\";\n\n/**\n * @title ERC721 Burnable Token\n * @dev ERC721 Token that can be burned (destroyed).\n */\nabstract contract ERC721Burnable is Context, ERC721 {\n /**\n * @dev Burns `tokenId`. See {ERC721-_burn}.\n *\n * Requirements:\n *\n * - The caller must own `tokenId` or be an approved operator.\n */\n function burn(uint256 tokenId) public virtual {\n //solhint-disable-next-line max-line-length\n require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: caller is not token owner nor approved\");\n _burn(tokenId);\n }\n}\n" }, "contracts/interfaces/IMint.sol": { "content": "// SPDX-License-Identifier: LGPL-3.0-only\npragma solidity ^0.8.0;\n\ninterface IMint {\n /// @notice overloaded function to be used by ERC721Handler\n function mint(\n address to,\n uint256 tokenId,\n string memory _data\n ) external;\n}\n" }, "@openzeppelin/contracts/token/ERC721/ERC721.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/ERC721.sol)\n\npragma solidity ^0.8.0;\n\nimport \"./IERC721.sol\";\nimport \"./IERC721Receiver.sol\";\nimport \"./extensions/IERC721Metadata.sol\";\nimport \"../../utils/Address.sol\";\nimport \"../../utils/Context.sol\";\nimport \"../../utils/Strings.sol\";\nimport \"../../utils/introspection/ERC165.sol\";\n\n/**\n * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including\n * the Metadata extension, but not including the Enumerable extension, which is available separately as\n * {ERC721Enumerable}.\n */\ncontract ERC721 is Context, ERC165, IERC721, IERC721Metadata {\n using Address for address;\n using Strings for uint256;\n\n // Token name\n string private _name;\n\n // Token symbol\n string private _symbol;\n\n // Mapping from token ID to owner address\n mapping(uint256 => address) private _owners;\n\n // Mapping owner address to token count\n mapping(address => uint256) private _balances;\n\n // Mapping from token ID to approved address\n mapping(uint256 => address) private _tokenApprovals;\n\n // Mapping from owner to operator approvals\n mapping(address => mapping(address => bool)) private _operatorApprovals;\n\n /**\n * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.\n */\n constructor(string memory name_, string memory symbol_) {\n _name = name_;\n _symbol = symbol_;\n }\n\n /**\n * @dev See {IERC165-supportsInterface}.\n */\n function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {\n return\n interfaceId == type(IERC721).interfaceId ||\n interfaceId == type(IERC721Metadata).interfaceId ||\n super.supportsInterface(interfaceId);\n }\n\n /**\n * @dev See {IERC721-balanceOf}.\n */\n function balanceOf(address owner) public view virtual override returns (uint256) {\n require(owner != address(0), \"ERC721: address zero is not a valid owner\");\n return _balances[owner];\n }\n\n /**\n * @dev See {IERC721-ownerOf}.\n */\n function ownerOf(uint256 tokenId) public view virtual override returns (address) {\n address owner = _owners[tokenId];\n require(owner != address(0), \"ERC721: invalid token ID\");\n return owner;\n }\n\n /**\n * @dev See {IERC721Metadata-name}.\n */\n function name() public view virtual override returns (string memory) {\n return _name;\n }\n\n /**\n * @dev See {IERC721Metadata-symbol}.\n */\n function symbol() public view virtual override returns (string memory) {\n return _symbol;\n }\n\n /**\n * @dev See {IERC721Metadata-tokenURI}.\n */\n function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {\n _requireMinted(tokenId);\n\n string memory baseURI = _baseURI();\n return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : \"\";\n }\n\n /**\n * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each\n * token will be the concatenation of the `baseURI` and the `tokenId`. Empty\n * by default, can be overridden in child contracts.\n */\n function _baseURI() internal view virtual returns (string memory) {\n return \"\";\n }\n\n /**\n * @dev See {IERC721-approve}.\n */\n function approve(address to, uint256 tokenId) public virtual override {\n address owner = ERC721.ownerOf(tokenId);\n require(to != owner, \"ERC721: approval to current owner\");\n\n require(\n _msgSender() == owner || isApprovedForAll(owner, _msgSender()),\n \"ERC721: approve caller is not token owner nor approved for all\"\n );\n\n _approve(to, tokenId);\n }\n\n /**\n * @dev See {IERC721-getApproved}.\n */\n function getApproved(uint256 tokenId) public view virtual override returns (address) {\n _requireMinted(tokenId);\n\n return _tokenApprovals[tokenId];\n }\n\n /**\n * @dev See {IERC721-setApprovalForAll}.\n */\n function setApprovalForAll(address operator, bool approved) public virtual override {\n _setApprovalForAll(_msgSender(), operator, approved);\n }\n\n /**\n * @dev See {IERC721-isApprovedForAll}.\n */\n function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {\n return _operatorApprovals[owner][operator];\n }\n\n /**\n * @dev See {IERC721-transferFrom}.\n */\n function transferFrom(\n address from,\n address to,\n uint256 tokenId\n ) public virtual override {\n //solhint-disable-next-line max-line-length\n require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: caller is not token owner nor approved\");\n\n _transfer(from, to, tokenId);\n }\n\n /**\n * @dev See {IERC721-safeTransferFrom}.\n */\n function safeTransferFrom(\n address from,\n address to,\n uint256 tokenId\n ) public virtual override {\n safeTransferFrom(from, to, tokenId, \"\");\n }\n\n /**\n * @dev See {IERC721-safeTransferFrom}.\n */\n function safeTransferFrom(\n address from,\n address to,\n uint256 tokenId,\n bytes memory data\n ) public virtual override {\n require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: caller is not token owner nor approved\");\n _safeTransfer(from, to, tokenId, data);\n }\n\n /**\n * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n *\n * `data` is additional data, it has no specified format and it is sent in call to `to`.\n *\n * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.\n * implement alternative mechanisms to perform token transfer, such as signature-based.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must exist and be owned by `from`.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function _safeTransfer(\n address from,\n address to,\n uint256 tokenId,\n bytes memory data\n ) internal virtual {\n _transfer(from, to, tokenId);\n require(_checkOnERC721Received(from, to, tokenId, data), \"ERC721: transfer to non ERC721Receiver implementer\");\n }\n\n /**\n * @dev Returns whether `tokenId` exists.\n *\n * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.\n *\n * Tokens start existing when they are minted (`_mint`),\n * and stop existing when they are burned (`_burn`).\n */\n function _exists(uint256 tokenId) internal view virtual returns (bool) {\n return _owners[tokenId] != address(0);\n }\n\n /**\n * @dev Returns whether `spender` is allowed to manage `tokenId`.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {\n address owner = ERC721.ownerOf(tokenId);\n return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);\n }\n\n /**\n * @dev Safely mints `tokenId` and transfers it to `to`.\n *\n * Requirements:\n *\n * - `tokenId` must not exist.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function _safeMint(address to, uint256 tokenId) internal virtual {\n _safeMint(to, tokenId, \"\");\n }\n\n /**\n * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is\n * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.\n */\n function _safeMint(\n address to,\n uint256 tokenId,\n bytes memory data\n ) internal virtual {\n _mint(to, tokenId);\n require(\n _checkOnERC721Received(address(0), to, tokenId, data),\n \"ERC721: transfer to non ERC721Receiver implementer\"\n );\n }\n\n /**\n * @dev Mints `tokenId` and transfers it to `to`.\n *\n * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible\n *\n * Requirements:\n *\n * - `tokenId` must not exist.\n * - `to` cannot be the zero address.\n *\n * Emits a {Transfer} event.\n */\n function _mint(address to, uint256 tokenId) internal virtual {\n require(to != address(0), \"ERC721: mint to the zero address\");\n require(!_exists(tokenId), \"ERC721: token already minted\");\n\n _beforeTokenTransfer(address(0), to, tokenId);\n\n _balances[to] += 1;\n _owners[tokenId] = to;\n\n emit Transfer(address(0), to, tokenId);\n\n _afterTokenTransfer(address(0), to, tokenId);\n }\n\n /**\n * @dev Destroys `tokenId`.\n * The approval is cleared when the token is burned.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n *\n * Emits a {Transfer} event.\n */\n function _burn(uint256 tokenId) internal virtual {\n address owner = ERC721.ownerOf(tokenId);\n\n _beforeTokenTransfer(owner, address(0), tokenId);\n\n // Clear approvals\n _approve(address(0), tokenId);\n\n _balances[owner] -= 1;\n delete _owners[tokenId];\n\n emit Transfer(owner, address(0), tokenId);\n\n _afterTokenTransfer(owner, address(0), tokenId);\n }\n\n /**\n * @dev Transfers `tokenId` from `from` to `to`.\n * As opposed to {transferFrom}, this imposes no restrictions on msg.sender.\n *\n * Requirements:\n *\n * - `to` cannot be the zero address.\n * - `tokenId` token must be owned by `from`.\n *\n * Emits a {Transfer} event.\n */\n function _transfer(\n address from,\n address to,\n uint256 tokenId\n ) internal virtual {\n require(ERC721.ownerOf(tokenId) == from, \"ERC721: transfer from incorrect owner\");\n require(to != address(0), \"ERC721: transfer to the zero address\");\n\n _beforeTokenTransfer(from, to, tokenId);\n\n // Clear approvals from the previous owner\n _approve(address(0), tokenId);\n\n _balances[from] -= 1;\n _balances[to] += 1;\n _owners[tokenId] = to;\n\n emit Transfer(from, to, tokenId);\n\n _afterTokenTransfer(from, to, tokenId);\n }\n\n /**\n * @dev Approve `to` to operate on `tokenId`\n *\n * Emits an {Approval} event.\n */\n function _approve(address to, uint256 tokenId) internal virtual {\n _tokenApprovals[tokenId] = to;\n emit Approval(ERC721.ownerOf(tokenId), to, tokenId);\n }\n\n /**\n * @dev Approve `operator` to operate on all of `owner` tokens\n *\n * Emits an {ApprovalForAll} event.\n */\n function _setApprovalForAll(\n address owner,\n address operator,\n bool approved\n ) internal virtual {\n require(owner != operator, \"ERC721: approve to caller\");\n _operatorApprovals[owner][operator] = approved;\n emit ApprovalForAll(owner, operator, approved);\n }\n\n /**\n * @dev Reverts if the `tokenId` has not been minted yet.\n */\n function _requireMinted(uint256 tokenId) internal view virtual {\n require(_exists(tokenId), \"ERC721: invalid token ID\");\n }\n\n /**\n * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.\n * The call is not executed if the target address is not a contract.\n *\n * @param from address representing the previous owner of the given token ID\n * @param to target address that will receive the tokens\n * @param tokenId uint256 ID of the token to be transferred\n * @param data bytes optional data to send along with the call\n * @return bool whether the call correctly returned the expected magic value\n */\n function _checkOnERC721Received(\n address from,\n address to,\n uint256 tokenId,\n bytes memory data\n ) private returns (bool) {\n if (to.isContract()) {\n try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {\n return retval == IERC721Receiver.onERC721Received.selector;\n } catch (bytes memory reason) {\n if (reason.length == 0) {\n revert(\"ERC721: transfer to non ERC721Receiver implementer\");\n } else {\n /// @solidity memory-safe-assembly\n assembly {\n revert(add(32, reason), mload(reason))\n }\n }\n }\n } else {\n return true;\n }\n }\n\n /**\n * @dev Hook that is called before any token transfer. This includes minting\n * and burning.\n *\n * Calling conditions:\n *\n * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be\n * transferred to `to`.\n * - When `from` is zero, `tokenId` will be minted for `to`.\n * - When `to` is zero, ``from``'s `tokenId` will be burned.\n * - `from` and `to` are never both zero.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _beforeTokenTransfer(\n address from,\n address to,\n uint256 tokenId\n ) internal virtual {}\n\n /**\n * @dev Hook that is called after any transfer of tokens. This includes\n * minting and burning.\n *\n * Calling conditions:\n *\n * - when `from` and `to` are both non-zero.\n * - `from` and `to` are never both zero.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _afterTokenTransfer(\n address from,\n address to,\n uint256 tokenId\n ) internal virtual {}\n}\n" }, "@openzeppelin/contracts/utils/Context.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n function _msgSender() internal view virtual returns (address) {\n return msg.sender;\n }\n\n function _msgData() internal view virtual returns (bytes calldata) {\n return msg.data;\n }\n}\n" }, "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @title ERC721 token receiver interface\n * @dev Interface for any contract that wants to support safeTransfers\n * from ERC721 asset contracts.\n */\ninterface IERC721Receiver {\n /**\n * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}\n * by `operator` from `from`, this function is called.\n *\n * It must return its Solidity selector to confirm the token transfer.\n * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.\n *\n * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.\n */\n function onERC721Received(\n address operator,\n address from,\n uint256 tokenId,\n bytes calldata data\n ) external returns (bytes4);\n}\n" }, "@openzeppelin/contracts/utils/Address.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)\n\npragma solidity ^0.8.1;\n\n/**\n * @dev Collection of functions related to the address type\n */\nlibrary Address {\n /**\n * @dev Returns true if `account` is a contract.\n *\n * [IMPORTANT]\n * ====\n * It is unsafe to assume that an address for which this function returns\n * false is an externally-owned account (EOA) and not a contract.\n *\n * Among others, `isContract` will return false for the following\n * types of addresses:\n *\n * - an externally-owned account\n * - a contract in construction\n * - an address where a contract will be created\n * - an address where a contract lived, but was destroyed\n * ====\n *\n * [IMPORTANT]\n * ====\n * You shouldn't rely on `isContract` to protect against flash loan attacks!\n *\n * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets\n * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract\n * constructor.\n * ====\n */\n function isContract(address account) internal view returns (bool) {\n // This method relies on extcodesize/address.code.length, which returns 0\n // for contracts in construction, since the code is only stored at the end\n // of the constructor execution.\n\n return account.code.length > 0;\n }\n\n /**\n * @dev Replacement for Solidity's `transfer`: sends `amount` wei to\n * `recipient`, forwarding all available gas and reverting on errors.\n *\n * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\n * of certain opcodes, possibly making contracts go over the 2300 gas limit\n * imposed by `transfer`, making them unable to receive funds via\n * `transfer`. {sendValue} removes this limitation.\n *\n * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\n *\n * IMPORTANT: because control is transferred to `recipient`, care must be\n * taken to not create reentrancy vulnerabilities. Consider using\n * {ReentrancyGuard} or the\n * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\n */\n function sendValue(address payable recipient, uint256 amount) internal {\n require(address(this).balance >= amount, \"Address: insufficient balance\");\n\n (bool success, ) = recipient.call{value: amount}(\"\");\n require(success, \"Address: unable to send value, recipient may have reverted\");\n }\n\n /**\n * @dev Performs a Solidity function call using a low level `call`. A\n * plain `call` is an unsafe replacement for a function call: use this\n * function instead.\n *\n * If `target` reverts with a revert reason, it is bubbled up by this\n * function (like regular Solidity function calls).\n *\n * Returns the raw returned data. To convert to the expected return value,\n * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\n *\n * Requirements:\n *\n * - `target` must be a contract.\n * - calling `target` with `data` must not revert.\n *\n * _Available since v3.1._\n */\n function functionCall(address target, bytes memory data) internal returns (bytes memory) {\n return functionCall(target, data, \"Address: low-level call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\n * `errorMessage` as a fallback revert reason when `target` reverts.\n *\n * _Available since v3.1._\n */\n function functionCall(\n address target,\n bytes memory data,\n string memory errorMessage\n ) internal returns (bytes memory) {\n return functionCallWithValue(target, data, 0, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but also transferring `value` wei to `target`.\n *\n * Requirements:\n *\n * - the calling contract must have an ETH balance of at least `value`.\n * - the called Solidity function must be `payable`.\n *\n * _Available since v3.1._\n */\n function functionCallWithValue(\n address target,\n bytes memory data,\n uint256 value\n ) internal returns (bytes memory) {\n return functionCallWithValue(target, data, value, \"Address: low-level call with value failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\n * with `errorMessage` as a fallback revert reason when `target` reverts.\n *\n * _Available since v3.1._\n */\n function functionCallWithValue(\n address target,\n bytes memory data,\n uint256 value,\n string memory errorMessage\n ) internal returns (bytes memory) {\n require(address(this).balance >= value, \"Address: insufficient balance for call\");\n require(isContract(target), \"Address: call to non-contract\");\n\n (bool success, bytes memory returndata) = target.call{value: value}(data);\n return verifyCallResult(success, returndata, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but performing a static call.\n *\n * _Available since v3.3._\n */\n function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {\n return functionStaticCall(target, data, \"Address: low-level static call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n * but performing a static call.\n *\n * _Available since v3.3._\n */\n function functionStaticCall(\n address target,\n bytes memory data,\n string memory errorMessage\n ) internal view returns (bytes memory) {\n require(isContract(target), \"Address: static call to non-contract\");\n\n (bool success, bytes memory returndata) = target.staticcall(data);\n return verifyCallResult(success, returndata, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but performing a delegate call.\n *\n * _Available since v3.4._\n */\n function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {\n return functionDelegateCall(target, data, \"Address: low-level delegate call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n * but performing a delegate call.\n *\n * _Available since v3.4._\n */\n function functionDelegateCall(\n address target,\n bytes memory data,\n string memory errorMessage\n ) internal returns (bytes memory) {\n require(isContract(target), \"Address: delegate call to non-contract\");\n\n (bool success, bytes memory returndata) = target.delegatecall(data);\n return verifyCallResult(success, returndata, errorMessage);\n }\n\n /**\n * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the\n * revert reason using the provided one.\n *\n * _Available since v4.3._\n */\n function verifyCallResult(\n bool success,\n bytes memory returndata,\n string memory errorMessage\n ) internal pure returns (bytes memory) {\n if (success) {\n return returndata;\n } else {\n // Look for revert reason and bubble it up if present\n if (returndata.length > 0) {\n // The easiest way to bubble the revert reason is using memory via assembly\n /// @solidity memory-safe-assembly\n assembly {\n let returndata_size := mload(returndata)\n revert(add(32, returndata), returndata_size)\n }\n } else {\n revert(errorMessage);\n }\n }\n }\n}\n" }, "@openzeppelin/contracts/utils/Strings.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev String operations.\n */\nlibrary Strings {\n bytes16 private constant _HEX_SYMBOLS = \"0123456789abcdef\";\n uint8 private constant _ADDRESS_LENGTH = 20;\n\n /**\n * @dev Converts a `uint256` to its ASCII `string` decimal representation.\n */\n function toString(uint256 value) internal pure returns (string memory) {\n // Inspired by OraclizeAPI's implementation - MIT licence\n // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol\n\n if (value == 0) {\n return \"0\";\n }\n uint256 temp = value;\n uint256 digits;\n while (temp != 0) {\n digits++;\n temp /= 10;\n }\n bytes memory buffer = new bytes(digits);\n while (value != 0) {\n digits -= 1;\n buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));\n value /= 10;\n }\n return string(buffer);\n }\n\n /**\n * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.\n */\n function toHexString(uint256 value) internal pure returns (string memory) {\n if (value == 0) {\n return \"0x00\";\n }\n uint256 temp = value;\n uint256 length = 0;\n while (temp != 0) {\n length++;\n temp >>= 8;\n }\n return toHexString(value, length);\n }\n\n /**\n * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.\n */\n function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {\n bytes memory buffer = new bytes(2 * length + 2);\n buffer[0] = \"0\";\n buffer[1] = \"x\";\n for (uint256 i = 2 * length + 1; i > 1; --i) {\n buffer[i] = _HEX_SYMBOLS[value & 0xf];\n value >>= 4;\n }\n require(value == 0, \"Strings: hex length insufficient\");\n return string(buffer);\n }\n\n /**\n * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.\n */\n function toHexString(address addr) internal pure returns (string memory) {\n return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);\n }\n}\n" }, "@openzeppelin/contracts/utils/introspection/ERC165.sol": { "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)\n\npragma solidity ^0.8.0;\n\nimport \"./IERC165.sol\";\n\n/**\n * @dev Implementation of the {IERC165} interface.\n *\n * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check\n * for the additional interface id that will be supported. For example:\n *\n * ```solidity\n * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n * return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);\n * }\n * ```\n *\n * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.\n */\nabstract contract ERC165 is IERC165 {\n /**\n * @dev See {IERC165-supportsInterface}.\n */\n function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n return interfaceId == type(IERC165).interfaceId;\n }\n}\n" } }, "settings": { "optimizer": { "enabled": true, "runs": 200 }, "outputSelection": { "*": { "*": [ "evm.bytecode", "evm.deployedBytecode", "devdoc", "userdoc", "metadata", "abi" ] } }, "libraries": {} } }