Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./ERC721Enumerable.sol";
import "./openzeppelin/ERC2981.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";
/**
* @title Fanchise Benefit NFT
*/
contract Benefit is VRFConsumerBaseV2, ERC721Enumerable, ERC2981, Ownable {
using ECDSA for bytes32;
uint256 constant UINT256_MAX = 2**256 - 1;
// Events
event BenefitClaimed(uint256 indexed benefitId, uint256 indexed nonce, uint256 tokenId);
event RaffleComplete(uint256 indexed raffleId, uint256 raffleWinner);
// Base URI
string private _baseURI;
// Mapping from nonce value to bool documenting whether the given nonce was already used, used to guard against replay attacks
mapping(uint256 => bool) private _nonceUsed;
// Used to lock owner configuration functions
bool private _locked;
// The address of the server that signs all buy transactions; see docs on the buy function for more info
address public _signerAddress;
// A record of the winner of a particular raffle (identified by a benefitId)
mapping(uint256 => uint256) _raffleWinners;
// A record of the number of participants in a given raffle
mapping(uint256 => uint256) _raffleParticipants;
// A record of the the chainlink request per raffle
mapping(uint256 => uint256) _raffleRequests;
// Chainlink configuration
VRFCoordinatorV2Interface COORDINATOR;
LinkTokenInterface LINKTOKEN;
uint64 chainlinkSubscriptionId;
bytes32 chainlinkKeyHash;
constructor(
string memory baseURI,
string memory name,
string memory symbol,
address owner,
address signer,
address royaltiesReceiver,
uint96 royaltiesFeeNumerator,
address vrfCoordinator,
address linkToken,
uint64 subscriptionId,
bytes32 keyHash
) ERC721(name, symbol) VRFConsumerBaseV2(vrfCoordinator) {
_baseURI = baseURI;
_signerAddress = signer;
_setDefaultRoyalty(royaltiesReceiver, royaltiesFeeNumerator);
transferOwnership(owner);
COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);
LINKTOKEN = LinkTokenInterface(linkToken);
chainlinkSubscriptionId = subscriptionId;
chainlinkKeyHash = keyHash;
}
/**
* Modifiers
*/
modifier unlocked() {
require(!_locked, "Contract locked");
_;
}
/**
* Public Transactions
*/
/**
* @notice Claim a benefit based on the holding of a Ballerz NFT.
* @param nonce The nonce of this transaction; must be unique to protect against replay attacks.
* @param sig The server's signature over all inputs: benefitId, nonce, this.address, msg.sender, msg.value
*/
function claim(
uint256 benefitId,
uint256 nonce,
bytes memory sig
) external payable {
require(!_nonceUsed[nonce], "Nonce already used");
require(_checkSig(nonce, msg.sender, msg.value, sig), "Invalid signature");
_claim(nonce);
emit BenefitClaimed(benefitId, nonce, latestTokenId());
}
/**
* Public View Functions
*/
function tokenURI(uint256 tokenId) public view override returns (string memory) {
require(_exists(tokenId), "Token does not exist.");
return string(abi.encodePacked(_baseURI, Strings.toString(tokenId)));
}
function totalSupply() public view virtual override returns (uint256) {
return _owners.length;
}
function latestTokenId() public view returns (uint256) {
return totalSupply() - 1;
}
function getRaffleWinner(uint256 raffleId) public view returns (uint256) {
return _raffleWinners[raffleId];
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/
function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
require(index < _owners.length, "ERC721Enumerable: global index out of bounds");
return index;
}
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId)
public
view
virtual
override(ERC2981, ERC721Enumerable)
returns (bool)
{
return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
}
/**
* Internal Functions
*/
function _claim(uint256 nonce) internal {
assert(!_nonceUsed[nonce]);
_nonceUsed[nonce] = true;
_safeMint(msg.sender);
}
function _setNumParticipants(uint256 raffleId, uint256 numParticipants) internal {
require(raffleId > 0, "Invalid raffleId");
require(_raffleParticipants[raffleId] == 0, "Raffle already begun");
require(numParticipants > 0, "Raffle must have at least one participant");
_raffleParticipants[raffleId] = numParticipants;
}
function _completeRaffle(uint256 raffleId, uint256 randomNumber) internal {
require(raffleId > 0, "Invalid raffleId");
require(_raffleWinners[raffleId] == 0, "Raffle already complete");
uint256 numParticipants = _raffleParticipants[raffleId];
uint256 raffleWinner = randomNumber % numParticipants;
_raffleWinners[raffleId] = raffleWinner;
emit RaffleComplete(raffleId, raffleWinner);
}
/**
* @dev Added nonce and contract address in sig to guard against replay attacks
*/
function _checkSig(
uint256 nonce,
address user,
uint256 price,
bytes memory sig
) internal view returns (bool) {
bytes32 hash = keccak256(
abi.encodePacked(
"\x19Ethereum Signed Message:\n32",
keccak256(abi.encode(nonce, address(this), user, price))
)
);
return _signerAddress == hash.recover(sig);
}
/**
* Owner Functions
*/
function setBaseURI(string memory baseURI) public onlyOwner unlocked {
_baseURI = baseURI;
}
function changeSigner(address signerAddress) public onlyOwner unlocked {
_signerAddress = signerAddress;
}
function lockContract() public onlyOwner {
_locked = true;
}
function withdraw(uint256 amount, address payable to) public onlyOwner {
require(amount <= address(this).balance, "Cannot withdraw more than current balance");
to.transfer(amount);
}
uint32 constant numWords = 1;
uint16 constant requestConfirmations = 3;
uint32 constant callbackGasLimit = 250000;
function chooseRaffleWinner(uint256 raffleId, uint256 numParticipants) public onlyOwner unlocked {
_setNumParticipants(raffleId, numParticipants);
require(chainlinkSubscriptionId > 0, "Chainlink subscriptionId not set");
// Will revert if subscription is not set and funded.
uint256 requestId = COORDINATOR.requestRandomWords(
chainlinkKeyHash,
chainlinkSubscriptionId,
requestConfirmations,
callbackGasLimit,
numWords
);
_raffleRequests[requestId] = raffleId;
}
function fulfillRandomWords(uint256 requestId, uint256[] memory randomWords) internal override {
uint256 raffleId = _raffleRequests[requestId];
_completeRaffle(raffleId, randomWords[0]);
}
/**
* @dev External onlyOwner version of {ERC2981-_setDefaultRoyalty}.
*/
function setDefaultRoyalty(address receiver, uint96 feeNumerator) external onlyOwner {
_setDefaultRoyalty(receiver, feeNumerator);
}
/**
* @dev External onlyOwner version of {ERC2981-_deleteDefaultRoyalty}.
*/
function deleteDefaultRoyalty() external onlyOwner {
_deleteDefaultRoyalty();
}
/**
* @dev External onlyOwner version of {ERC2981-_setTokenRoyalty}.
*/
function setTokenRoyalty(
uint256 tokenId,
address receiver,
uint96 feeNumerator
) external onlyOwner {
_setTokenRoyalty(tokenId, receiver, feeNumerator);
}
/**
* @dev External onlyOwner version of {ERC2981-_resetTokenRoyalty}.
*/
function resetTokenRoyalty(uint256 tokenId) external onlyOwner {
_resetTokenRoyalty(tokenId);
}
/**
* @dev Update chainlink subscriptionId
*/
function setChainlinkSubscriptionId(uint64 subscriptionId) external onlyOwner {
chainlinkSubscriptionId = subscriptionId;
}
/**
* @dev Update chainlink subscriptionId
*/
function setChainlinkKeyHash(bytes32 keyHash) external onlyOwner {
chainlinkKeyHash = keyHash;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol";
/**
* @dev This implements an optional extension of {ERC721} defined in the EIP that adds
* enumerability of all the token ids in the contract as well as all token ids owned by each
* account but rips out the core of the gas-wasting processing that comes from OpenZeppelin.
*/
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721Enumerable-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _owners.length;
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/
function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
require(index < _owners.length, "ERC721Enumerable: global index out of bounds");
return index;
}
/**
* @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
*/
function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256 tokenId) {
require(index < balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
uint count;
for(uint i; i < _owners.length; i++){
if(owner == _owners[i]){
if(count == index) return i;
else count++;
}
}
revert("ERC721Enumerable: owner index out of bounds");
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/common/ERC2981.sol)
pragma solidity ^0.8.0;
import "./IERC2981.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";
/**
* @dev Implementation of the NFT Royalty Standard, a standardized way to retrieve royalty payment information.
*
* Royalty information can be specified globally for all token ids via {_setDefaultRoyalty}, and/or individually for
* specific token ids via {_setTokenRoyalty}. The latter takes precedence over the first.
*
* Royalty is specified as a fraction of sale price. {_feeDenominator} is overridable but defaults to 10000, meaning the
* fee is specified in basis points by default.
*
* IMPORTANT: ERC-2981 only specifies a way to signal royalty information and does not enforce its payment. See
* https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments[Rationale] in the EIP. Marketplaces are expected to
* voluntarily pay royalties together with sales, but note that this standard is not yet widely supported.
*
* _Available since v4.5._
*/
abstract contract ERC2981 is IERC2981, ERC165 {
struct RoyaltyInfo {
address receiver;
uint96 royaltyFraction;
}
RoyaltyInfo private _defaultRoyaltyInfo;
mapping(uint256 => RoyaltyInfo) private _tokenRoyaltyInfo;
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC165) returns (bool) {
return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
}
/**
* @inheritdoc IERC2981
*/
function royaltyInfo(uint256 _tokenId, uint256 _salePrice) external view override returns (address, uint256) {
RoyaltyInfo memory royalty = _tokenRoyaltyInfo[_tokenId];
if (royalty.receiver == address(0)) {
royalty = _defaultRoyaltyInfo;
}
uint256 royaltyAmount = (_salePrice * royalty.royaltyFraction) / _feeDenominator();
return (royalty.receiver, royaltyAmount);
}
/**
* @dev The denominator with which to interpret the fee set in {_setTokenRoyalty} and {_setDefaultRoyalty} as a
* fraction of the sale price. Defaults to 10000 so fees are expressed in basis points, but may be customized by an
* override.
*/
function _feeDenominator() internal pure virtual returns (uint96) {
return 10000;
}
/**
* @dev Sets the royalty information that all ids in this contract will default to.
*
* Requirements:
*
* - `receiver` cannot be the zero address.
* - `feeNumerator` cannot be greater than the fee denominator.
*/
function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal virtual {
require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
require(receiver != address(0), "ERC2981: invalid receiver");
_defaultRoyaltyInfo = RoyaltyInfo(receiver, feeNumerator);
}
/**
* @dev Removes default royalty information.
*/
function _deleteDefaultRoyalty() internal virtual {
delete _defaultRoyaltyInfo;
}
/**
* @dev Sets the royalty information for a specific token id, overriding the global default.
*
* Requirements:
*
* - `tokenId` must be already minted.
* - `receiver` cannot be the zero address.
* - `feeNumerator` cannot be greater than the fee denominator.
*/
function _setTokenRoyalty(
uint256 tokenId,
address receiver,
uint96 feeNumerator
) internal virtual {
require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
require(receiver != address(0), "ERC2981: Invalid parameters");
_tokenRoyaltyInfo[tokenId] = RoyaltyInfo(receiver, feeNumerator);
}
/**
* @dev Resets royalty information for the token id back to the global default.
*/
function _resetTokenRoyalty(uint256 tokenId) internal virtual {
delete _tokenRoyaltyInfo[tokenId];
}
}
// SPDX-License-Identifier: MIT
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 () {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
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 {
emit OwnershipTransferred(_owner, address(0));
_owner = 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");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
*
* These functions can be used to verify that a message was signed by the holder
* of the private keys of a given address.
*/
library ECDSA {
/**
* @dev Returns the address that signed a hashed message (`hash`) with
* `signature`. This address can then be used for verification purposes.
*
* The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
* this function rejects them by requiring the `s` value to be in the lower
* half order, and the `v` value to be either 27 or 28.
*
* IMPORTANT: `hash` _must_ be the result of a hash operation for the
* verification to be secure: it is possible to craft signatures that
* recover to arbitrary addresses for non-hashed data. A safe way to ensure
* this is by receiving a hash of the original message (which may otherwise
* be too long), and then calling {toEthSignedMessageHash} on it.
*/
function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
// Divide the signature in r, s and v variables
bytes32 r;
bytes32 s;
uint8 v;
// Check the signature length
// - case 65: r,s,v signature (standard)
// - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
if (signature.length == 65) {
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
// solhint-disable-next-line no-inline-assembly
assembly {
r := mload(add(signature, 0x20))
s := mload(add(signature, 0x40))
v := byte(0, mload(add(signature, 0x60)))
}
} else if (signature.length == 64) {
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
// solhint-disable-next-line no-inline-assembly
assembly {
let vs := mload(add(signature, 0x40))
r := mload(add(signature, 0x20))
s := and(vs, 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
v := add(shr(255, vs), 27)
}
} else {
revert("ECDSA: invalid signature length");
}
return recover(hash, v, r, s);
}
/**
* @dev Overload of {ECDSA-recover} that receives the `v`,
* `r` and `s` signature fields separately.
*/
function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
// EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
// unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
// the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
// signatures from current libraries generate a unique signature with an s-value in the lower half order.
//
// If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
// with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
// vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
// these malleable signatures as well.
require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "ECDSA: invalid signature 's' value");
require(v == 27 || v == 28, "ECDSA: invalid signature 'v' value");
// If the signature is valid (and not malleable), return the signer address
address signer = ecrecover(hash, v, r, s);
require(signer != address(0), "ECDSA: invalid signature");
return signer;
}
/**
* @dev Returns an Ethereum Signed Message, created from a `hash`. This
* produces hash corresponding to the one signed with the
* https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
* JSON-RPC method as part of EIP-191.
*
* See {recover}.
*/
function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
// 32 is the length in bytes of hash,
// enforced by the type signature above
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
}
/**
* @dev Returns an Ethereum Signed Typed Data, created from a
* `domainSeparator` and a `structHash`. This produces hash corresponding
* to the one signed with the
* https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
* JSON-RPC method as part of EIP-712.
*
* See {recover}.
*/
function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface LinkTokenInterface {
function allowance(address owner, address spender) external view returns (uint256 remaining);
function approve(address spender, uint256 value) external returns (bool success);
function balanceOf(address owner) external view returns (uint256 balance);
function decimals() external view returns (uint8 decimalPlaces);
function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
function increaseApproval(address spender, uint256 subtractedValue) external;
function name() external view returns (string memory tokenName);
function symbol() external view returns (string memory tokenSymbol);
function totalSupply() external view returns (uint256 totalTokensIssued);
function transfer(address to, uint256 value) external returns (bool success);
function transferAndCall(
address to,
uint256 value,
bytes calldata data
) external returns (bool success);
function transferFrom(
address from,
address to,
uint256 value
) external returns (bool success);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface VRFCoordinatorV2Interface {
/**
* @notice Get configuration relevant for making requests
* @return minimumRequestConfirmations global min for request confirmations
* @return maxGasLimit global max for request gas limit
* @return s_provingKeyHashes list of registered key hashes
*/
function getRequestConfig()
external
view
returns (
uint16,
uint32,
bytes32[] memory
);
/**
* @notice Request a set of random words.
* @param keyHash - Corresponds to a particular oracle job which uses
* that key for generating the VRF proof. Different keyHash's have different gas price
* ceilings, so you can select a specific one to bound your maximum per request cost.
* @param subId - The ID of the VRF subscription. Must be funded
* with the minimum subscription balance required for the selected keyHash.
* @param minimumRequestConfirmations - How many blocks you'd like the
* oracle to wait before responding to the request. See SECURITY CONSIDERATIONS
* for why you may want to request more. The acceptable range is
* [minimumRequestBlockConfirmations, 200].
* @param callbackGasLimit - How much gas you'd like to receive in your
* fulfillRandomWords callback. Note that gasleft() inside fulfillRandomWords
* may be slightly less than this amount because of gas used calling the function
* (argument decoding etc.), so you may need to request slightly more than you expect
* to have inside fulfillRandomWords. The acceptable range is
* [0, maxGasLimit]
* @param numWords - The number of uint256 random values you'd like to receive
* in your fulfillRandomWords callback. Note these numbers are expanded in a
* secure way by the VRFCoordinator from a single random value supplied by the oracle.
* @return requestId - A unique identifier of the request. Can be used to match
* a request to a response in fulfillRandomWords.
*/
function requestRandomWords(
bytes32 keyHash,
uint64 subId,
uint16 minimumRequestConfirmations,
uint32 callbackGasLimit,
uint32 numWords
) external returns (uint256 requestId);
/**
* @notice Create a VRF subscription.
* @return subId - A unique subscription id.
* @dev You can manage the consumer set dynamically with addConsumer/removeConsumer.
* @dev Note to fund the subscription, use transferAndCall. For example
* @dev LINKTOKEN.transferAndCall(
* @dev address(COORDINATOR),
* @dev amount,
* @dev abi.encode(subId));
*/
function createSubscription() external returns (uint64 subId);
/**
* @notice Get a VRF subscription.
* @param subId - ID of the subscription
* @return balance - LINK balance of the subscription in juels.
* @return reqCount - number of requests for this subscription, determines fee tier.
* @return owner - owner of the subscription.
* @return consumers - list of consumer address which are able to use this subscription.
*/
function getSubscription(uint64 subId)
external
view
returns (
uint96 balance,
uint64 reqCount,
address owner,
address[] memory consumers
);
/**
* @notice Request subscription owner transfer.
* @param subId - ID of the subscription
* @param newOwner - proposed new owner of the subscription
*/
function requestSubscriptionOwnerTransfer(uint64 subId, address newOwner) external;
/**
* @notice Request subscription owner transfer.
* @param subId - ID of the subscription
* @dev will revert if original owner of subId has
* not requested that msg.sender become the new owner.
*/
function acceptSubscriptionOwnerTransfer(uint64 subId) external;
/**
* @notice Add a consumer to a VRF subscription.
* @param subId - ID of the subscription
* @param consumer - New consumer which can use the subscription
*/
function addConsumer(uint64 subId, address consumer) external;
/**
* @notice Remove a consumer from a VRF subscription.
* @param subId - ID of the subscription
* @param consumer - Consumer to remove from the subscription
*/
function removeConsumer(uint64 subId, address consumer) external;
/**
* @notice Cancel a subscription
* @param subId - ID of the subscription
* @param to - Where to send the remaining LINK to
*/
function cancelSubscription(uint64 subId, address to) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/** ****************************************************************************
* @notice Interface for contracts using VRF randomness
* *****************************************************************************
* @dev PURPOSE
*
* @dev Reggie the Random Oracle (not his real job) wants to provide randomness
* @dev to Vera the verifier in such a way that Vera can be sure he's not
* @dev making his output up to suit himself. Reggie provides Vera a public key
* @dev to which he knows the secret key. Each time Vera provides a seed to
* @dev Reggie, he gives back a value which is computed completely
* @dev deterministically from the seed and the secret key.
*
* @dev Reggie provides a proof by which Vera can verify that the output was
* @dev correctly computed once Reggie tells it to her, but without that proof,
* @dev the output is indistinguishable to her from a uniform random sample
* @dev from the output space.
*
* @dev The purpose of this contract is to make it easy for unrelated contracts
* @dev to talk to Vera the verifier about the work Reggie is doing, to provide
* @dev simple access to a verifiable source of randomness. It ensures 2 things:
* @dev 1. The fulfillment came from the VRFCoordinator
* @dev 2. The consumer contract implements fulfillRandomWords.
* *****************************************************************************
* @dev USAGE
*
* @dev Calling contracts must inherit from VRFConsumerBase, and can
* @dev initialize VRFConsumerBase's attributes in their constructor as
* @dev shown:
*
* @dev contract VRFConsumer {
* @dev constructor(<other arguments>, address _vrfCoordinator, address _link)
* @dev VRFConsumerBase(_vrfCoordinator) public {
* @dev <initialization with other arguments goes here>
* @dev }
* @dev }
*
* @dev The oracle will have given you an ID for the VRF keypair they have
* @dev committed to (let's call it keyHash). Create subscription, fund it
* @dev and your consumer contract as a consumer of it (see VRFCoordinatorInterface
* @dev subscription management functions).
* @dev Call requestRandomWords(keyHash, subId, minimumRequestConfirmations,
* @dev callbackGasLimit, numWords),
* @dev see (VRFCoordinatorInterface for a description of the arguments).
*
* @dev Once the VRFCoordinator has received and validated the oracle's response
* @dev to your request, it will call your contract's fulfillRandomWords method.
*
* @dev The randomness argument to fulfillRandomWords is a set of random words
* @dev generated from your requestId and the blockHash of the request.
*
* @dev If your contract could have concurrent requests open, you can use the
* @dev requestId returned from requestRandomWords to track which response is associated
* @dev with which randomness request.
* @dev See "SECURITY CONSIDERATIONS" for principles to keep in mind,
* @dev if your contract could have multiple requests in flight simultaneously.
*
* @dev Colliding `requestId`s are cryptographically impossible as long as seeds
* @dev differ.
*
* *****************************************************************************
* @dev SECURITY CONSIDERATIONS
*
* @dev A method with the ability to call your fulfillRandomness method directly
* @dev could spoof a VRF response with any random value, so it's critical that
* @dev it cannot be directly called by anything other than this base contract
* @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
*
* @dev For your users to trust that your contract's random behavior is free
* @dev from malicious interference, it's best if you can write it so that all
* @dev behaviors implied by a VRF response are executed *during* your
* @dev fulfillRandomness method. If your contract must store the response (or
* @dev anything derived from it) and use it later, you must ensure that any
* @dev user-significant behavior which depends on that stored value cannot be
* @dev manipulated by a subsequent VRF request.
*
* @dev Similarly, both miners and the VRF oracle itself have some influence
* @dev over the order in which VRF responses appear on the blockchain, so if
* @dev your contract could have multiple VRF requests in flight simultaneously,
* @dev you must ensure that the order in which the VRF responses arrive cannot
* @dev be used to manipulate your contract's user-significant behavior.
*
* @dev Since the block hash of the block which contains the requestRandomness
* @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
* @dev miner could, in principle, fork the blockchain to evict the block
* @dev containing the request, forcing the request to be included in a
* @dev different block with a different hash, and therefore a different input
* @dev to the VRF. However, such an attack would incur a substantial economic
* @dev cost. This cost scales with the number of blocks the VRF oracle waits
* @dev until it calls responds to a request. It is for this reason that
* @dev that you can signal to an oracle you'd like them to wait longer before
* @dev responding to the request (however this is not enforced in the contract
* @dev and so remains effective only in the case of unmodified oracle software).
*/
abstract contract VRFConsumerBaseV2 {
error OnlyCoordinatorCanFulfill(address have, address want);
address private immutable vrfCoordinator;
/**
* @param _vrfCoordinator address of VRFCoordinator contract
*/
constructor(address _vrfCoordinator) {
vrfCoordinator = _vrfCoordinator;
}
/**
* @notice fulfillRandomness handles the VRF response. Your contract must
* @notice implement it. See "SECURITY CONSIDERATIONS" above for important
* @notice principles to keep in mind when implementing your fulfillRandomness
* @notice method.
*
* @dev VRFConsumerBaseV2 expects its subcontracts to have a method with this
* @dev signature, and will call it once it has verified the proof
* @dev associated with the randomness. (It is triggered via a call to
* @dev rawFulfillRandomness, below.)
*
* @param requestId The Id initially returned by requestRandomness
* @param randomWords the VRF output expanded to the requested number of words
*/
function fulfillRandomWords(uint256 requestId, uint256[] memory randomWords) internal virtual;
// rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
// proof. rawFulfillRandomness then calls fulfillRandomness, after validating
// the origin of the call
function rawFulfillRandomWords(uint256 requestId, uint256[] memory randomWords) external {
if (msg.sender != vrfCoordinator) {
revert OnlyCoordinatorCanFulfill(msg.sender, vrfCoordinator);
}
fulfillRandomWords(requestId, randomWords);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";
import "./Address.sol";
abstract contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
using Address for address;
using Strings for uint256;
string private _name;
string private _symbol;
// Mapping from token ID to owner address
address[] internal _owners;
mapping(uint256 => address) private _tokenApprovals;
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: balance query for the zero address");
uint256 count;
for (uint256 i; i < _owners.length; ++i) {
if (owner == _owners[i]) ++count;
}
return count;
}
/**
* @dev See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view virtual override returns (address) {
address owner = _owners[tokenId];
require(owner != address(0), "ERC721: owner query for nonexistent token");
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 {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 owner nor approved for all"
);
_approve(to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId) public view virtual override returns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved) public virtual override {
require(operator != _msgSender(), "ERC721: approve to caller");
_operatorApprovals[_msgSender()][operator] = approved;
emit ApprovalForAll(_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: transfer caller is not owner nor 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: transfer caller is not owner nor 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 tokenId < _owners.length && _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) {
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
address owner = ERC721.ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, 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) internal virtual {
_safeMint(to, "");
}
/**
* @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, bytes memory _data) internal virtual {
uint256 tokenId = _mint(to);
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) internal virtual returns (uint256) {
require(to != address(0), "ERC721: mint to the zero address");
uint256 tokenId = _owners.length;
_owners.push(to);
emit Transfer(address(0), to, tokenId);
return tokenId;
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/
function _burn(uint256 tokenId) internal virtual {
address owner = ERC721.ownerOf(tokenId);
// Clear approvals
_approve(address(0), tokenId);
_owners[tokenId] = address(0);
emit Transfer(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 of token that is not own");
require(to != address(0), "ERC721: transfer to the zero address");
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_owners[tokenId] = to;
emit Transfer(from, to, tokenId);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/
function _approve(address to, uint256 tokenId) internal virtual {
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
}
/**
* @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 {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
} else {
return true;
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
interface IERC721Enumerable is IERC721 {
/**
* @dev Returns the total amount of tokens stored by the contract.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns a token ID owned by `owner` at a given `index` of its token list.
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
*/
function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);
/**
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
* Use along with {totalSupply} to enumerate all tokens.
*/
function tokenByIndex(uint256 index) external view returns (uint256);
}
// SPDX-License-Identifier: MIT
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`, 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 be 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 Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId) external view returns (address operator);
/**
* @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 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);
/**
* @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;
}
// SPDX-License-Identifier: MIT
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 `IERC721.onERC721Received.selector`.
*/
function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
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
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) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev String operations.
*/
library Strings {
bytes16 private constant alphabet = "0123456789abcdef";
/**
* @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] = alphabet[value & 0xf];
value >>= 4;
}
require(value == 0, "Strings: hex length insufficient");
return string(buffer);
}
}
// SPDX-License-Identifier: MIT
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
pragma solidity ^0.8.6;
library Address {
function isContract(address account) internal view returns (bool) {
uint size;
assembly {
size := extcodesize(account)
}
return size > 0;
}
}
// SPDX-License-Identifier: MIT
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
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC2981.sol)
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/utils/introspection/IERC165.sol";
/**
* @dev Interface for the NFT Royalty Standard.
*
* A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal
* support for royalty payments across all NFT marketplaces and ecosystem participants.
*
* _Available since v4.5._
*/
interface IERC2981 is IERC165 {
/**
* @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of
* exchange. The royalty amount is denominated and should be payed in that same unit of exchange.
*/
function royaltyInfo(uint256 tokenId, uint256 salePrice)
external
view
returns (address receiver, uint256 royaltyAmount);
}