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LSP8IdentifiableDigitalAsset

LSP8IdentifiableDigitalAsset

Standard Specifications

LSP-8-IdentifiableDigitalAsset

Solidity implementation

LSP8IdentifiableDigitalAsset.sol

Implementation of a LSP8 Identifiable Digital Asset, a contract that represents a non-fungible token.

Standard implementation contract of the LSP8 standard. Minting and transferring are done by providing a unique tokenId. This implementation is agnostic to the way tokens are created. A supply mechanism has to be added in a derived contract using _mint For a generic mechanism, see LSP7Mintable.

Public Methods​

Public methods are accessible externally from users, allowing interaction with this function from dApps or other smart contracts. When marked as 'public', a method can be called both externally and internally, on the other hand, when marked as 'external', a method can only be called externally.

fallback​

References
fallback(bytes calldata callData) external payable returns (bytes memory);

The fallback function was called with the following amount of native tokens: msg.value; and the following calldata: callData.

Achieves the goal of LSP-17-ContractExtension standard by extending the contract to handle calls of functions that do not exist natively, forwarding the function call to the extension address mapped to the function being called. This function is executed when:

  • Sending data of length less than 4 bytes to the contract.

  • The first 4 bytes of the calldata do not match any publicly callable functions from the contract ABI.

  • Receiving native tokens

  1. If the data is equal or longer than 4 bytes, the ERC-725Y storage is queried with the following data key: _LSP17_EXTENSION_PREFIX + bytes4(msg.sig) (Check LSP-2-ERC725YJSONSchema for encoding the data key)

  • If there is no address stored under the following data key, revert with NoExtensionFoundForFunctionSelector(bytes4). The data key relative to bytes4(0) is an exception, where no reverts occurs if there is no extension address stored under. This exception is made to allow users to send random data (graffiti) to the account and to be able to react on it.

  • If there is an address, forward the msg.data to the extension using the CALL opcode, appending 52 bytes (20 bytes of msg.sender and 32 bytes of msg.value). Return what the calls returns, or revert if the call failed.

  1. If the data sent to this function is of length less than 4 bytes (not a function selector), revert.

authorizeOperator​

References
function authorizeOperator(
  address operator,
  bytes32 tokenId,
  bytes operatorNotificationData
) external nonpayable;

Allow an operator address to transfer or burn a specific tokenId on behalf of its token owner. See isOperatorFor.

Parameters​

NameTypeDescription
operatoraddressThe address to authorize as an operator.
tokenIdbytes32The token ID operator has access to.
operatorNotificationDatabytesThe data to notify the operator about via LSP1.

balanceOf​

References
function balanceOf(address tokenOwner) external view returns (uint256);

Get the number of token IDs owned by tokenOwner.

Parameters​

NameTypeDescription
tokenOwneraddressThe address to query *

Returns​

NameTypeDescription
0uint256The total number of token IDs that tokenOwner owns.

getData​

References
function getData(bytes32 dataKey) external view returns (bytes dataValue);

Reading the ERC725Y storage for data key dataKey returned the following value: dataValue.

Get in the ERC725Y storage the bytes data stored at a specific data key dataKey.

Parameters​

NameTypeDescription
dataKeybytes32The data key for which to retrieve the value.

Returns​

NameTypeDescription
dataValuebytesThe bytes value stored under the specified data key.

getDataBatch​

References
function getDataBatch(
  bytes32[] dataKeys
) external view returns (bytes[] dataValues);

Reading the ERC725Y storage for data keys dataKeys returned the following values: dataValues.

Get in the ERC725Y storage the bytes data stored at multiple data keys dataKeys.

Parameters​

NameTypeDescription
dataKeysbytes32[]The array of keys which values to retrieve

Returns​

NameTypeDescription
dataValuesbytes[]The array of data stored at multiple keys

getOperatorsOf​

References
function getOperatorsOf(bytes32 tokenId) external view returns (address[]);

Returns all operator addresses that are allowed to transfer or burn a specific tokenId on behalf of its owner.

Parameters​

NameTypeDescription
tokenIdbytes32The token ID to get the operators for.

Returns​

NameTypeDescription
0address[]An array of operators allowed to transfer or burn a specific tokenId. Requirements - tokenId must exist.

isOperatorFor​

References
function isOperatorFor(
  address operator,
  bytes32 tokenId
) external view returns (bool);

Returns whether operator address is an operator for a given tokenId.

Parameters​

NameTypeDescription
operatoraddressThe address to query operator status for.
tokenIdbytes32The token ID to check if operator is allowed to operate on.

Returns​

NameTypeDescription
0booltrue if operator is an operator for tokenId, false otherwise.

owner​

References
function owner() external view returns (address);

Returns the address of the current owner.

Returns​

NameTypeDescription
0address-

renounceOwnership​

References
function renounceOwnership() external nonpayable;

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.


revokeOperator​

References
function revokeOperator(
  address operator,
  bytes32 tokenId,
  bytes operatorNotificationData
) external nonpayable;

Remove access of operator for a given tokenId, disallowing it to transfer tokenId on behalf of its owner. See also isOperatorFor.

Parameters​

NameTypeDescription
operatoraddressThe address to revoke as an operator.
tokenIdbytes32The tokenId operator is revoked from operating on.
operatorNotificationDatabytesThe data to notify the operator about via LSP1.

setData​

References
Warning

Note for developers: despite the fact that this function is set as payable, if the function is not intended to receive value (= native tokens), an additional check should be implemented to ensure that msg.value sent was equal to 0.

function setData(bytes32 dataKey, bytes dataValue) external payable;

Setting the following data key value pair in the ERC725Y storage. Data key: dataKey, data value: dataValue.

Sets a single bytes value dataValue in the ERC725Y storage for a specific data key dataKey. The function is marked as payable to enable flexibility on child contracts. For instance to implement a fee mechanism for setting specific data.

Requirements:

  • SHOULD only be callable by the owner.

Emitted events:

Parameters​

NameTypeDescription
dataKeybytes32The data key for which to set a new value.
dataValuebytesThe new bytes value to set.

setDataBatch​

References
Warning

Note for developers: despite the fact that this function is set as payable, if the function is not intended to receive value (= native tokens), an additional check should be implemented to ensure that msg.value sent was equal to 0.

function setDataBatch(bytes32[] dataKeys, bytes[] dataValues) external payable;

Setting the following data key value pairs in the ERC725Y storage. Data keys: dataKeys, data values: dataValues.

Batch data setting function that behaves the same as setData but allowing to set multiple data key/value pairs in the ERC725Y storage in the same transaction.

Requirements:

  • SHOULD only be callable by the owner of the contract.

Emitted events:

Parameters​

NameTypeDescription
dataKeysbytes32[]An array of data keys to set bytes values for.
dataValuesbytes[]An array of bytes values to set for each dataKeys.

supportsInterface​

References
function supportsInterface(bytes4 interfaceId) external view returns (bool);

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.

Parameters​

NameTypeDescription
interfaceIdbytes4-

Returns​

NameTypeDescription
0bool-

tokenIdsOf​

References
function tokenIdsOf(address tokenOwner) external view returns (bytes32[]);

Returns the list of token IDs that the tokenOwner address owns.

Parameters​

NameTypeDescription
tokenOwneraddressThe address that we want to get the list of token IDs for.

Returns​

NameTypeDescription
0bytes32[]An array of bytes32[] tokenIds owned by tokenOwner.

tokenOwnerOf​

References
function tokenOwnerOf(bytes32 tokenId) external view returns (address);

Returns the list of tokenIds for the tokenOwner address.

Parameters​

NameTypeDescription
tokenIdbytes32tokenOwner The address to query owned tokens

Returns​

NameTypeDescription
0addressThe owner address of the given tokenId.

totalSupply​

References
function totalSupply() external view returns (uint256);

Returns the number of existing tokens that have been minted in this contract.

Returns​

NameTypeDescription
0uint256The number of existing tokens.

transfer​

References
function transfer(
  address from,
  address to,
  bytes32 tokenId,
  bool allowNonLSP1Recipient,
  bytes data
) external nonpayable;

Transfer a given tokenId token from the from address to the to address. If operators are set for a specific tokenId, all the operators are revoked after the tokenId have been transferred. The allowNonLSP1Recipient parameter MUST be set to true when transferring tokens to Externally Owned Accounts (EOAs) or contracts that do not implement the LSP1 standard.

Parameters​

NameTypeDescription
fromaddressThe address that owns the given tokenId.
toaddressThe address that will receive the tokenId.
tokenIdbytes32The token ID to transfer.
allowNonLSP1RecipientboolWhen set to true, the to address CAN be any addres. When set to false, the to address MUST be a contract that supports the LSP1 UniversalReceiver standard.
databytesAny additional data the caller wants included in the emitted event, and sent in the hooks of the from and to addresses.

transferBatch​

References
function transferBatch(
  address[] from,
  address[] to,
  bytes32[] tokenId,
  bool[] allowNonLSP1Recipient,
  bytes[] data
) external nonpayable;

Transfers multiple tokens at once based on the arrays of from, to and tokenId. If any transfer fails, the whole call will revert.

Parameters​

NameTypeDescription
fromaddress[]An array of sending addresses.
toaddress[]An array of recipient addresses.
tokenIdbytes32[]An array of token IDs to transfer.
allowNonLSP1Recipientbool[]When set to true, to may be any address. When set to false, to must be a contract that supports the LSP1 standard and not revert.
databytes[]Any additional data the caller wants included in the emitted event, and sent in the hooks to the from and to addresses.

transferOwnership​

References
function transferOwnership(address newOwner) external nonpayable;

Transfers ownership of the contract to a new account (newOwner). Can only be called by the current owner.

Parameters​

NameTypeDescription
newOwneraddress-

Internal Methods​

Any method labeled as internal serves as utility function within the contract. They can be used when writing solidity contracts that inherit from this contract. These methods can be extended or modified by overriding their internal behavior to suit specific needs.

Internal functions cannot be called externally, whether from other smart contracts, dApp interfaces, or backend services. Their restricted accessibility ensures that they remain exclusively available within the context of the current contract, promoting controlled and encapsulated usage of these internal utilities.

_checkOwner​

function _checkOwner() internal view;

Throws if the sender is not the owner.


_setOwner​

function _setOwner(address newOwner) internal nonpayable;

Changes the owner if newOwner and oldOwner are different This pattern is useful in inheritance.


_getData​

function _getData(bytes32 dataKey) internal view returns (bytes dataValue);

Read the value stored under a specific dataKey inside the underlying ERC725Y storage, represented as a mapping of bytes32 data keys mapped to their bytes data values.

mapping(bytes32 => bytes) _store

Parameters​

NameTypeDescription
dataKeybytes32A bytes32 data key to read the associated bytes value from the store.

Returns​

NameTypeDescription
dataValuebytesThe bytes value associated with the given dataKey in the ERC725Y storage.

_setData​

function _setData(bytes32 dataKey, bytes dataValue) internal nonpayable;

Save gas by emitting the DataChanged event with only the first 256 bytes of dataValue


_isOperatorOrOwner​

function _isOperatorOrOwner(
  address caller,
  bytes32 tokenId
) internal view returns (bool);

verifies if the caller is operator or owner for the tokenId

Returns​

NameTypeDescription
0booltrue if caller is either operator or owner

_revokeOperator​

function _revokeOperator(
  address operator,
  address tokenOwner,
  bytes32 tokenId,
  bytes operatorNotificationData
) internal nonpayable;

removes operator from the list of operators for the tokenId


_clearOperators​

function _clearOperators(
  address tokenOwner,
  bytes32 tokenId
) internal nonpayable;

revoke all the current operators for a specific tokenId token which belongs to tokenOwner.

Parameters​

NameTypeDescription
tokenOwneraddressThe address that is the owner of the tokenId.
tokenIdbytes32The token to remove the associated operators for.

_exists​

function _exists(bytes32 tokenId) internal view returns (bool);

Returns whether tokenId exists. Tokens start existing when they are minted (_mint), and stop existing when they are burned (_burn).


_existsOrError​

function _existsOrError(bytes32 tokenId) internal view;

When tokenId does not exist then revert with an error.


_mint​

function _mint(
  address to,
  bytes32 tokenId,
  bool allowNonLSP1Recipient,
  bytes data
) internal nonpayable;

Create tokenId by minting it and transfers it to to.

Emitted events:

  • Transfer event with address(0) as from address.

Parameters​

NameTypeDescription
toaddress@param tokenId The token ID to create (= mint).
tokenIdbytes32The token ID to create (= mint).
allowNonLSP1RecipientboolWhen set to true, to may be any address. When set to false, to must be a contract that supports the LSP1 standard.
databytesAny additional data the caller wants included in the emitted event, and sent in the hook of the to address.

_burn​

Hint

In dApps, you can know which addresses are burning tokens by listening for the Transfer event and filter with the zero address as to.

function _burn(bytes32 tokenId, bytes data) internal nonpayable;

Burn a specific tokenId, removing the tokenId from the tokenIdsOf the caller and decreasing its balanceOf by -1. This will also clear all the operators allowed to transfer the tokenId. The owner of the tokenId will be notified about the tokenId being transferred through its LSP1 universalReceiver function, if it is a contract that supports the LSP1 interface. Its universalReceiver function will receive all the parameters in the calldata packed encoded. Any logic in the _beforeTokenTransfer function will run before burning tokenId and updating the balances.

Emitted events:

  • Transfer event with address(0) as the to address.

Parameters​

NameTypeDescription
tokenIdbytes32The token to burn.
databytesAny additional data the caller wants included in the emitted event, and sent in the LSP1 hook on the token owner's address.

_transfer​

danger

This internal function does not check if the sender is authorized or not to operate on the tokenId.

function _transfer(
  address from,
  address to,
  bytes32 tokenId,
  bool allowNonLSP1Recipient,
  bytes data
) internal nonpayable;

Change the owner of the tokenId from from to to. Both the sender and recipient will be notified of the tokenId being transferred through their LSP1 universalReceiver function, if they are contracts that support the LSP1 interface. Their universalReceiver function will receive all the parameters in the calldata packed encoded. Any logic in the _beforeTokenTransfer function will run before changing the owner of tokenId.

Emitted events:

Parameters​

NameTypeDescription
fromaddressThe sender address.
toaddress@param tokenId The token to transfer.
tokenIdbytes32The token to transfer.
allowNonLSP1RecipientboolWhen set to true, to may be any address. When set to false, to must be a contract that supports the LSP1 standard.
databytesAdditional data the caller wants included in the emitted event, and sent in the hooks to from and to addresses.

_beforeTokenTransfer​

function _beforeTokenTransfer(
  address from,
  address to,
  bytes32 tokenId
) internal nonpayable;

Hook that is called before any token transfer, including minting and burning.

  • Allows to run custom logic before updating balances and notifiying sender/recipient by overriding this function.

Parameters​

NameTypeDescription
fromaddressThe sender address
toaddress@param tokenId The tokenId to transfer
tokenIdbytes32The tokenId to transfer

_notifyTokenOperator​

function _notifyTokenOperator(
  address operator,
  bytes lsp1Data
) internal nonpayable;

Attempt to notify the operator operator about the tokenId tokens being authorized. This is done by calling its universalReceiver function with the _TYPEID_LSP8_TOKENOPERATOR as typeId, if operator is a contract that supports the LSP1 interface. If operator is an EOA or a contract that does not support the LSP1 interface, nothing will happen and no notification will be sent.

Parameters​

NameTypeDescription
operatoraddressThe address to call the {universalReceiver} function on.
lsp1Databytesthe data to be sent to the operator address in the universalReceiver call.

_notifyTokenSender​

function _notifyTokenSender(address from, bytes lsp1Data) internal nonpayable;

An attempt is made to notify the token sender about the tokenId changing owners using LSP1 interface.


_notifyTokenReceiver​

function _notifyTokenReceiver(
  address to,
  bool allowNonLSP1Recipient,
  bytes lsp1Data
) internal nonpayable;

An attempt is made to notify the token receiver about the tokenId changing owners using LSP1 interface. When allowNonLSP1Recipient is FALSE the token receiver MUST support LSP1. The receiver may revert when the token being sent is not wanted.


_supportsInterfaceInERC165Extension​

function _supportsInterfaceInERC165Extension(
  bytes4 interfaceId
) internal view returns (bool);

Returns whether the interfaceId being checked is supported in the extension of the supportsInterface selector. To be used by extendable contracts wishing to extend the ERC165 interfaceIds originally supported by reading whether the interfaceId queried is supported in the supportsInterface extension if the extension is set, if not it returns false.


_getExtension​

function _getExtension(bytes4 functionSelector) internal view returns (address);

Returns the extension address stored under the following data key:

  • _LSP17_EXTENSION_PREFIX + <bytes4> (Check [LSP2-ERC725YJSONSchema] for encoding the data key).

  • If no extension is stored, returns the address(0).


_fallbackLSP17Extendable​

function _fallbackLSP17Extendable(
  bytes callData
) internal nonpayable returns (bytes);

Forwards the call with the received value to an extension mapped to a function selector. Calls _getExtension to get the address of the extension mapped to the function selector being called on the account. If there is no extension, the address(0) will be returned. Reverts if there is no extension for the function being called. If there is an extension for the function selector being called, it calls the extension with the CALL opcode, passing the msg.data appended with the 20 bytes of the msg.sender and 32 bytes of the msg.value Because the function uses assembly return()/revert() to terminate the call, it cannot be called before other codes in fallback(). Otherwise, the codes after _fallbackLSP17Extendable() may never be reached.


Events​

AuthorizedOperator​

References
event AuthorizedOperator(address indexed operator, address indexed tokenOwner, bytes32 indexed tokenId, bytes operatorNotificationData);

Emitted when tokenOwner enables operator to transfer or burn the tokenId.

Parameters​

NameTypeDescription
operator indexedaddressThe address authorized as an operator.
tokenOwner indexedaddressThe owner of the tokenId.
tokenId indexedbytes32The tokenId operator address has access on behalf of tokenOwner.
operatorNotificationDatabytesThe data to notify the operator about via LSP1.

DataChanged​

References
event DataChanged(bytes32 indexed dataKey, bytes dataValue);

The following data key/value pair has been changed in the ERC725Y storage: Data key: dataKey, data value: dataValue.

Emitted when data at a specific dataKey was changed to a new value dataValue.

Parameters​

NameTypeDescription
dataKey indexedbytes32The data key for which a bytes value is set.
dataValuebytesThe value to set for the given data key.

OwnershipTransferred​

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

Parameters​

NameTypeDescription
previousOwner indexedaddress-
newOwner indexedaddress-

RevokedOperator​

References
event RevokedOperator(address indexed operator, address indexed tokenOwner, bytes32 indexed tokenId, bytes operatorNotificationData);

Emitted when tokenOwner disables operator to transfer or burn tokenId on its behalf.

Parameters​

NameTypeDescription
operator indexedaddressThe address revoked from the operator array ({getOperatorsOf}).
tokenOwner indexedaddressThe owner of the tokenId.
tokenId indexedbytes32The tokenId operator is revoked from operating on.
operatorNotificationDatabytesThe data to notify the operator about via LSP1.

Transfer​

References
event Transfer(address operator, address indexed from, address indexed to, bytes32 indexed tokenId, bool allowNonLSP1Recipient, bytes data);

Emitted when tokenId token is transferred from the from to the to address.

Parameters​

NameTypeDescription
operatoraddressThe address of operator that sent the tokenId
from indexedaddressThe previous owner of the tokenId
to indexedaddressThe new owner of tokenId
tokenId indexedbytes32The tokenId that was transferred
allowNonLSP1RecipientboolIf the token transfer enforces the to recipient address to be a contract that implements the LSP1 standard or not.
databytesAny additional data the caller included by the caller during the transfer, and sent in the hooks to the from and to addresses.

Errors​

ERC725Y_DataKeysValuesEmptyArray​

References
error ERC725Y_DataKeysValuesEmptyArray();

Reverts when one of the array parameter provided to setDataBatch function is an empty array.


ERC725Y_DataKeysValuesLengthMismatch​

References
error ERC725Y_DataKeysValuesLengthMismatch();

Reverts when there is not the same number of elements in the datakeys and dataValues array parameters provided when calling the setDataBatch function.


ERC725Y_MsgValueDisallowed​

References
error ERC725Y_MsgValueDisallowed();

Reverts when sending value to the setData or setDataBatch function.


InvalidExtensionAddress​

References
error InvalidExtensionAddress(bytes storedData);

reverts when the bytes retrieved from the LSP17 data key is not a valid address (not 20 bytes)

Parameters​

NameTypeDescription
storedDatabytes-

InvalidFunctionSelector​

References
error InvalidFunctionSelector(bytes data);

reverts when the contract is called with a function selector not valid (less than 4 bytes of data)

Parameters​

NameTypeDescription
databytes-

LSP4TokenNameNotEditable​

References
error LSP4TokenNameNotEditable();

Reverts when trying to edit the data key LSP4TokenName after the digital asset contract has been deployed. The LSP4TokenName data key is located inside the ERC725Y Data key-value store of the digital asset contract. It can be set only once inside the constructor/initializer when the digital asset contract is being deployed.


LSP4TokenSymbolNotEditable​

References
error LSP4TokenSymbolNotEditable();

Reverts when trying to edit the data key LSP4TokenSymbol after the digital asset contract has been deployed. The LSP4TokenSymbol data key is located inside the ERC725Y Data key-value store of the digital asset contract. It can be set only once inside the constructor/initializer when the digital asset contract is being deployed.


LSP8CannotSendToAddressZero​

References
error LSP8CannotSendToAddressZero();

reverts when trying to send token to the zero address.


LSP8CannotSendToSelf​

References
error LSP8CannotSendToSelf();

reverts when specifying the same address for from and to in a token transfer.


LSP8CannotUseAddressZeroAsOperator​

References
error LSP8CannotUseAddressZeroAsOperator();

reverts when trying to set the zero address as an operator.


LSP8InvalidTransferBatch​

References
error LSP8InvalidTransferBatch();

reverts when the parameters used for transferBatch have different lengths.


LSP8NonExistentTokenId​

References
error LSP8NonExistentTokenId(bytes32 tokenId);

reverts when tokenId has not been minted.

Parameters​

NameTypeDescription
tokenIdbytes32-

LSP8NonExistingOperator​

References
error LSP8NonExistingOperator(address operator, bytes32 tokenId);

reverts when operator is not an operator for the tokenId.

Parameters​

NameTypeDescription
operatoraddress-
tokenIdbytes32-

LSP8NotTokenOperator​

References
error LSP8NotTokenOperator(bytes32 tokenId, address caller);

reverts when caller is not an allowed operator for tokenId.

Parameters​

NameTypeDescription
tokenIdbytes32-
calleraddress-

LSP8NotTokenOwner​

References
error LSP8NotTokenOwner(address tokenOwner, bytes32 tokenId, address caller);

reverts when caller is not the tokenOwner of the tokenId.

Parameters​

NameTypeDescription
tokenOwneraddress-
tokenIdbytes32-
calleraddress-

LSP8NotifyTokenReceiverContractMissingLSP1Interface​

References
error LSP8NotifyTokenReceiverContractMissingLSP1Interface(
  address tokenReceiver
);

reverts if the tokenReceiver does not implement LSP1 when minting or transferring tokens with bool allowNonLSP1Recipient set as false.

Parameters​

NameTypeDescription
tokenReceiveraddress-

LSP8NotifyTokenReceiverIsEOA​

References
error LSP8NotifyTokenReceiverIsEOA(address tokenReceiver);

reverts if the tokenReceiver is an EOA when minting or transferring tokens with bool allowNonLSP1Recipient set as false.

Parameters​

NameTypeDescription
tokenReceiveraddress-

LSP8OperatorAlreadyAuthorized​

References
error LSP8OperatorAlreadyAuthorized(address operator, bytes32 tokenId);

reverts when operator is already authorized for the tokenId.

Parameters​

NameTypeDescription
operatoraddress-
tokenIdbytes32-

LSP8TokenOwnerCannotBeOperator​

References
error LSP8TokenOwnerCannotBeOperator();

reverts when trying to authorize or revoke the token's owner as an operator.


NoExtensionFoundForFunctionSelector​

References
error NoExtensionFoundForFunctionSelector(bytes4 functionSelector);

reverts when there is no extension for the function selector being called with

Parameters​

NameTypeDescription
functionSelectorbytes4-