Contract Name:
KogakeCarbon
Contract Source Code:
// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.7;
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "./ERC721A.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
interface IERC20Mintable {
function mint(address account_, uint256 amount_) external;
function decimals() external view returns (uint8);
}
contract KogakeCarbon is ERC721A, Ownable, ReentrancyGuard {
using SafeERC20 for IERC20;
bool public mintStarted = false;
bool public mintWhitelistStarted = false;
mapping(address => bool) public blacklist;
mapping(address => uint16) public whitelist;
uint256 internal batchLimit = 5;
uint256 public constant mintPrice = 0.055 ether;
uint256 private constant maxNFTs = 5555;
uint256 private constant fee = 20;
string private URI = "https://api.kogakecarbon.com/nft/";
address public treasuryAddr;
address public tokenAddr;
constructor(address _treasury, address _token)
ERC721A("Kogake Carbon", "KogakeCarbon")
{
require(_treasury != address(0) && _token != address(0), "zero addr");
treasuryAddr = _treasury;
tokenAddr = _token;
}
function mint(uint256 amount) public payable {
require(blacklist[msg.sender] != true, "User is blacklisted");
require(mintStarted, "Mint is not started");
require(amount <= batchLimit && amount != 0, "Not in batch limit");
require(msg.value >= mintPrice * amount, "Not enough ether");
require(_totalMinted() + amount < maxNFTs, "Too much to mint");
_mintLogic(amount);
}
function whitelistMint(uint256 amount) public {
require(blacklist[msg.sender] != true, "User is blacklisted");
require(mintWhitelistStarted, "Mint for whitelist is not started");
require(_totalMinted() + amount < maxNFTs, "Too much to mint");
require(
whitelistMintable() >= amount && amount != 0,
"Over minting limit"
);
_mintLogic(amount);
whitelist[msg.sender] -= uint16(amount);
}
function _mintLogic(uint256 amount) internal nonReentrant {
_safeMint(msg.sender, amount);
IERC20Mintable(tokenAddr).mint(
msg.sender,
10**IERC20Mintable(tokenAddr).decimals() * amount
);
}
function whitelistMintable() public view returns (uint256) {
return whitelist[msg.sender];
}
function _baseURI() internal view override returns (string memory) {
return URI;
}
function setBaseURI(string memory newBaseURI) external onlyOwner {
URI = newBaseURI;
}
function mintedTotal() public view returns (uint256) {
return _totalMinted();
}
function totalMintable() public pure returns (uint256) {
return maxNFTs;
}
function startMint() external onlyOwner {
mintStarted = true;
}
function pauseMint() external onlyOwner {
mintStarted = false;
}
function startWhitelistMint() external onlyOwner {
mintWhitelistStarted = true;
}
function pauseWhitelistMint() external onlyOwner {
mintWhitelistStarted = false;
}
function updateBlacklist(address[] memory users, bool[] memory blackListed)
external
onlyOwner
{
uint256 length = users.length;
require(length == blackListed.length);
for (uint256 i = 0; i < length; i++) {
blacklist[users[i]] = blackListed[i];
}
}
function updateWhitelist(
address[] memory users,
uint16[] memory allowedMechs
) external onlyOwner {
uint256 length = users.length;
require(length == allowedMechs.length);
for (uint256 i = 0; i < length; i++) {
whitelist[users[i]] = allowedMechs[i];
}
}
function withdraw() public onlyOwner {
uint256 value = address(this).balance;
uint256 feeToSend = (value * fee) / 100;
uint256 treasuryPayout = value - feeToSend;
(bool success, ) = payable(treasuryAddr).call{value: treasuryPayout}(
""
);
require(success, "Transfer to treasury failed");
(success, ) = payable(owner()).call{value: feeToSend}("");
require(success, "Fee transfer failed");
payable(owner()).transfer(address(this).balance);
}
function recoverERC20(address tokenAddress, uint256 tokenAmount)
external
onlyOwner
{
IERC20(tokenAddress).safeTransfer(msg.sender, tokenAmount);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(
IERC20 token,
address spender,
uint256 value
) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
// Return data is optional
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import "./IERC721A.sol";
/**
* @dev ERC721 token receiver interface.
*/
interface ERC721A__IERC721Receiver {
function onERC721Received(
address operator,
address from,
uint256 tokenId,
bytes calldata data
) external returns (bytes4);
}
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata extension. Built to optimize for lower gas during batch mints.
*
* Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
*
* Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
*
* Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
*/
contract ERC721A is IERC721A {
// Mask of an entry in packed address data.
uint256 private constant BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1;
// The bit position of `numberMinted` in packed address data.
uint256 private constant BITPOS_NUMBER_MINTED = 64;
// The bit position of `numberBurned` in packed address data.
uint256 private constant BITPOS_NUMBER_BURNED = 128;
// The bit position of `aux` in packed address data.
uint256 private constant BITPOS_AUX = 192;
// Mask of all 256 bits in packed address data except the 64 bits for `aux`.
uint256 private constant BITMASK_AUX_COMPLEMENT = (1 << 192) - 1;
// The bit position of `startTimestamp` in packed ownership.
uint256 private constant BITPOS_START_TIMESTAMP = 160;
// The bit mask of the `burned` bit in packed ownership.
uint256 private constant BITMASK_BURNED = 1 << 224;
// The bit position of the `nextInitialized` bit in packed ownership.
uint256 private constant BITPOS_NEXT_INITIALIZED = 225;
// The bit mask of the `nextInitialized` bit in packed ownership.
uint256 private constant BITMASK_NEXT_INITIALIZED = 1 << 225;
// The tokenId of the next token to be minted.
uint256 private _currentIndex;
// The number of tokens burned.
uint256 private _burnCounter;
// Token name
string private _name;
// Token symbol
string private _symbol;
// Mapping from token ID to ownership details
// An empty struct value does not necessarily mean the token is unowned.
// See `_packedOwnershipOf` implementation for details.
//
// Bits Layout:
// - [0..159] `addr`
// - [160..223] `startTimestamp`
// - [224] `burned`
// - [225] `nextInitialized`
mapping(uint256 => uint256) private _packedOwnerships;
// Mapping owner address to address data.
//
// Bits Layout:
// - [0..63] `balance`
// - [64..127] `numberMinted`
// - [128..191] `numberBurned`
// - [192..255] `aux`
mapping(address => uint256) private _packedAddressData;
// Mapping from token ID to approved address.
mapping(uint256 => address) private _tokenApprovals;
// Mapping from owner to operator approvals
mapping(address => mapping(address => bool)) private _operatorApprovals;
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
_currentIndex = _startTokenId();
}
/**
* @dev Returns the starting token ID.
* To change the starting token ID, please override this function.
*/
function _startTokenId() internal view virtual returns (uint256) {
return 0;
}
/**
* @dev Returns the next token ID to be minted.
*/
function _nextTokenId() internal view returns (uint256) {
return _currentIndex;
}
/**
* @dev Returns the total number of tokens in existence.
* Burned tokens will reduce the count.
* To get the total number of tokens minted, please see `_totalMinted`.
*/
function totalSupply() public view override returns (uint256) {
// Counter underflow is impossible as _burnCounter cannot be incremented
// more than `_currentIndex - _startTokenId()` times.
unchecked {
return _currentIndex - _burnCounter - _startTokenId();
}
}
/**
* @dev Returns the total amount of tokens minted in the contract.
*/
function _totalMinted() internal view returns (uint256) {
// Counter underflow is impossible as _currentIndex does not decrement,
// and it is initialized to `_startTokenId()`
unchecked {
return _currentIndex - _startTokenId();
}
}
/**
* @dev Returns the total number of tokens burned.
*/
function _totalBurned() internal view returns (uint256) {
return _burnCounter;
}
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId)
public
view
virtual
override
returns (bool)
{
// The interface IDs are constants representing the first 4 bytes of the XOR of
// all function selectors in the interface. See: https://eips.ethereum.org/EIPS/eip-165
// e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`
return
interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165.
interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721.
interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata.
}
/**
* @dev See {IERC721-balanceOf}.
*/
function balanceOf(address owner) public view override returns (uint256) {
if (owner == address(0)) revert BalanceQueryForZeroAddress();
return _packedAddressData[owner] & BITMASK_ADDRESS_DATA_ENTRY;
}
/**
* Returns the number of tokens minted by `owner`.
*/
function _numberMinted(address owner) internal view returns (uint256) {
return
(_packedAddressData[owner] >> BITPOS_NUMBER_MINTED) &
BITMASK_ADDRESS_DATA_ENTRY;
}
/**
* Returns the number of tokens burned by or on behalf of `owner`.
*/
function _numberBurned(address owner) internal view returns (uint256) {
return
(_packedAddressData[owner] >> BITPOS_NUMBER_BURNED) &
BITMASK_ADDRESS_DATA_ENTRY;
}
/**
* Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
*/
function _getAux(address owner) internal view returns (uint64) {
return uint64(_packedAddressData[owner] >> BITPOS_AUX);
}
/**
* Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
* If there are multiple variables, please pack them into a uint64.
*/
function _setAux(address owner, uint64 aux) internal {
uint256 packed = _packedAddressData[owner];
uint256 auxCasted;
assembly {
// Cast aux without masking.
auxCasted := aux
}
packed = (packed & BITMASK_AUX_COMPLEMENT) | (auxCasted << BITPOS_AUX);
_packedAddressData[owner] = packed;
}
/**
* Returns the packed ownership data of `tokenId`.
*/
function _packedOwnershipOf(uint256 tokenId)
private
view
returns (uint256)
{
uint256 curr = tokenId;
unchecked {
if (_startTokenId() <= curr)
if (curr < _currentIndex) {
uint256 packed = _packedOwnerships[curr];
// If not burned.
if (packed & BITMASK_BURNED == 0) {
// Invariant:
// There will always be an ownership that has an address and is not burned
// before an ownership that does not have an address and is not burned.
// Hence, curr will not underflow.
//
// We can directly compare the packed value.
// If the address is zero, packed is zero.
while (packed == 0) {
packed = _packedOwnerships[--curr];
}
return packed;
}
}
}
revert OwnerQueryForNonexistentToken();
}
/**
* Returns the unpacked `TokenOwnership` struct from `packed`.
*/
function _unpackedOwnership(uint256 packed)
private
pure
returns (TokenOwnership memory ownership)
{
ownership.addr = address(uint160(packed));
ownership.startTimestamp = uint64(packed >> BITPOS_START_TIMESTAMP);
ownership.burned = packed & BITMASK_BURNED != 0;
}
/**
* Returns the unpacked `TokenOwnership` struct at `index`.
*/
function _ownershipAt(uint256 index)
internal
view
returns (TokenOwnership memory)
{
return _unpackedOwnership(_packedOwnerships[index]);
}
/**
* @dev Initializes the ownership slot minted at `index` for efficiency purposes.
*/
function _initializeOwnershipAt(uint256 index) internal {
if (_packedOwnerships[index] == 0) {
_packedOwnerships[index] = _packedOwnershipOf(index);
}
}
/**
* Gas spent here starts off proportional to the maximum mint batch size.
* It gradually moves to O(1) as tokens get transferred around in the collection over time.
*/
function _ownershipOf(uint256 tokenId)
internal
view
returns (TokenOwnership memory)
{
return _unpackedOwnership(_packedOwnershipOf(tokenId));
}
/**
* @dev See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view override returns (address) {
return address(uint160(_packedOwnershipOf(tokenId)));
}
/**
* @dev See {IERC721Metadata-name}.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/
function tokenURI(uint256 tokenId)
public
view
virtual
override
returns (string memory)
{
if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
string memory baseURI = _baseURI();
return
bytes(baseURI).length != 0
? string(abi.encodePacked(baseURI, _toString(tokenId)))
: "";
}
/**
* @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
* token will be the concatenation of the `baseURI` and the `tokenId`. Empty
* by default, can be overriden in child contracts.
*/
function _baseURI() internal view virtual returns (string memory) {
return "";
}
/**
* @dev Casts the address to uint256 without masking.
*/
function _addressToUint256(address value)
private
pure
returns (uint256 result)
{
assembly {
result := value
}
}
/**
* @dev Casts the boolean to uint256 without branching.
*/
function _boolToUint256(bool value) private pure returns (uint256 result) {
assembly {
result := value
}
}
/**
* @dev See {IERC721-approve}.
*/
function approve(address to, uint256 tokenId) public override {
address owner = address(uint160(_packedOwnershipOf(tokenId)));
if (to == owner) revert ApprovalToCurrentOwner();
if (_msgSenderERC721A() != owner)
if (!isApprovedForAll(owner, _msgSenderERC721A())) {
revert ApprovalCallerNotOwnerNorApproved();
}
_tokenApprovals[tokenId] = to;
emit Approval(owner, to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId)
public
view
override
returns (address)
{
if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved)
public
virtual
override
{
if (operator == _msgSenderERC721A()) revert ApproveToCaller();
_operatorApprovals[_msgSenderERC721A()][operator] = approved;
emit ApprovalForAll(_msgSenderERC721A(), 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 {
_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 {
_transfer(from, to, tokenId);
if (to.code.length != 0)
if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
revert TransferToNonERC721ReceiverImplementer();
}
}
/**
* @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`),
*/
function _exists(uint256 tokenId) internal view returns (bool) {
return
_startTokenId() <= tokenId &&
tokenId < _currentIndex && // If within bounds,
_packedOwnerships[tokenId] & BITMASK_BURNED == 0; // and not burned.
}
/**
* @dev Equivalent to `_safeMint(to, quantity, '')`.
*/
function _safeMint(address to, uint256 quantity) internal {
_safeMint(to, quantity, "");
}
/**
* @dev Safely mints `quantity` tokens and transfers them to `to`.
*
* Requirements:
*
* - If `to` refers to a smart contract, it must implement
* {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
* - `quantity` must be greater than 0.
*
* Emits a {Transfer} event.
*/
function _safeMint(
address to,
uint256 quantity,
bytes memory _data
) internal {
uint256 startTokenId = _currentIndex;
if (to == address(0)) revert MintToZeroAddress();
if (quantity == 0) revert MintZeroQuantity();
_beforeTokenTransfers(address(0), to, startTokenId, quantity);
// Overflows are incredibly unrealistic.
// balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
// updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
unchecked {
// Updates:
// - `balance += quantity`.
// - `numberMinted += quantity`.
//
// We can directly add to the balance and number minted.
_packedAddressData[to] +=
quantity *
((1 << BITPOS_NUMBER_MINTED) | 1);
// Updates:
// - `address` to the owner.
// - `startTimestamp` to the timestamp of minting.
// - `burned` to `false`.
// - `nextInitialized` to `quantity == 1`.
_packedOwnerships[startTokenId] =
_addressToUint256(to) |
(block.timestamp << BITPOS_START_TIMESTAMP) |
(_boolToUint256(quantity == 1) << BITPOS_NEXT_INITIALIZED);
uint256 updatedIndex = startTokenId;
uint256 end = updatedIndex + quantity;
if (to.code.length != 0) {
do {
emit Transfer(address(0), to, updatedIndex);
if (
!_checkContractOnERC721Received(
address(0),
to,
updatedIndex++,
_data
)
) {
revert TransferToNonERC721ReceiverImplementer();
}
} while (updatedIndex < end);
// Reentrancy protection
if (_currentIndex != startTokenId) revert();
} else {
do {
emit Transfer(address(0), to, updatedIndex++);
} while (updatedIndex < end);
}
_currentIndex = updatedIndex;
}
_afterTokenTransfers(address(0), to, startTokenId, quantity);
}
/**
* @dev Mints `quantity` tokens and transfers them to `to`.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `quantity` must be greater than 0.
*
* Emits a {Transfer} event.
*/
function _mint(address to, uint256 quantity) internal {
uint256 startTokenId = _currentIndex;
if (to == address(0)) revert MintToZeroAddress();
if (quantity == 0) revert MintZeroQuantity();
_beforeTokenTransfers(address(0), to, startTokenId, quantity);
// Overflows are incredibly unrealistic.
// balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
// updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
unchecked {
// Updates:
// - `balance += quantity`.
// - `numberMinted += quantity`.
//
// We can directly add to the balance and number minted.
_packedAddressData[to] +=
quantity *
((1 << BITPOS_NUMBER_MINTED) | 1);
// Updates:
// - `address` to the owner.
// - `startTimestamp` to the timestamp of minting.
// - `burned` to `false`.
// - `nextInitialized` to `quantity == 1`.
_packedOwnerships[startTokenId] =
_addressToUint256(to) |
(block.timestamp << BITPOS_START_TIMESTAMP) |
(_boolToUint256(quantity == 1) << BITPOS_NEXT_INITIALIZED);
uint256 updatedIndex = startTokenId;
uint256 end = updatedIndex + quantity;
do {
emit Transfer(address(0), to, updatedIndex++);
} while (updatedIndex < end);
_currentIndex = updatedIndex;
}
_afterTokenTransfers(address(0), to, startTokenId, quantity);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
*
* 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
) private {
uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
if (address(uint160(prevOwnershipPacked)) != from)
revert TransferFromIncorrectOwner();
bool isApprovedOrOwner = (_msgSenderERC721A() == from ||
isApprovedForAll(from, _msgSenderERC721A()) ||
getApproved(tokenId) == _msgSenderERC721A());
if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
if (to == address(0)) revert TransferToZeroAddress();
_beforeTokenTransfers(from, to, tokenId, 1);
// Clear approvals from the previous owner.
delete _tokenApprovals[tokenId];
// Underflow of the sender's balance is impossible because we check for
// ownership above and the recipient's balance can't realistically overflow.
// Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
unchecked {
// We can directly increment and decrement the balances.
--_packedAddressData[from]; // Updates: `balance -= 1`.
++_packedAddressData[to]; // Updates: `balance += 1`.
// Updates:
// - `address` to the next owner.
// - `startTimestamp` to the timestamp of transfering.
// - `burned` to `false`.
// - `nextInitialized` to `true`.
_packedOwnerships[tokenId] =
_addressToUint256(to) |
(block.timestamp << BITPOS_START_TIMESTAMP) |
BITMASK_NEXT_INITIALIZED;
// If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
if (prevOwnershipPacked & BITMASK_NEXT_INITIALIZED == 0) {
uint256 nextTokenId = tokenId + 1;
// If the next slot's address is zero and not burned (i.e. packed value is zero).
if (_packedOwnerships[nextTokenId] == 0) {
// If the next slot is within bounds.
if (nextTokenId != _currentIndex) {
// Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
_packedOwnerships[nextTokenId] = prevOwnershipPacked;
}
}
}
}
emit Transfer(from, to, tokenId);
_afterTokenTransfers(from, to, tokenId, 1);
}
/**
* @dev Equivalent to `_burn(tokenId, false)`.
*/
function _burn(uint256 tokenId) internal virtual {
_burn(tokenId, false);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/
function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
address from = address(uint160(prevOwnershipPacked));
if (approvalCheck) {
bool isApprovedOrOwner = (_msgSenderERC721A() == from ||
isApprovedForAll(from, _msgSenderERC721A()) ||
getApproved(tokenId) == _msgSenderERC721A());
if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
}
_beforeTokenTransfers(from, address(0), tokenId, 1);
// Clear approvals from the previous owner.
delete _tokenApprovals[tokenId];
// Underflow of the sender's balance is impossible because we check for
// ownership above and the recipient's balance can't realistically overflow.
// Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
unchecked {
// Updates:
// - `balance -= 1`.
// - `numberBurned += 1`.
//
// We can directly decrement the balance, and increment the number burned.
// This is equivalent to `packed -= 1; packed += 1 << BITPOS_NUMBER_BURNED;`.
_packedAddressData[from] += (1 << BITPOS_NUMBER_BURNED) - 1;
// Updates:
// - `address` to the last owner.
// - `startTimestamp` to the timestamp of burning.
// - `burned` to `true`.
// - `nextInitialized` to `true`.
_packedOwnerships[tokenId] =
_addressToUint256(from) |
(block.timestamp << BITPOS_START_TIMESTAMP) |
BITMASK_BURNED |
BITMASK_NEXT_INITIALIZED;
// If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
if (prevOwnershipPacked & BITMASK_NEXT_INITIALIZED == 0) {
uint256 nextTokenId = tokenId + 1;
// If the next slot's address is zero and not burned (i.e. packed value is zero).
if (_packedOwnerships[nextTokenId] == 0) {
// If the next slot is within bounds.
if (nextTokenId != _currentIndex) {
// Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
_packedOwnerships[nextTokenId] = prevOwnershipPacked;
}
}
}
}
emit Transfer(from, address(0), tokenId);
_afterTokenTransfers(from, address(0), tokenId, 1);
// Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
unchecked {
_burnCounter++;
}
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target 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 _checkContractOnERC721Received(
address from,
address to,
uint256 tokenId,
bytes memory _data
) private returns (bool) {
try
ERC721A__IERC721Receiver(to).onERC721Received(
_msgSenderERC721A(),
from,
tokenId,
_data
)
returns (bytes4 retval) {
return
retval ==
ERC721A__IERC721Receiver(to).onERC721Received.selector;
} catch (bytes memory reason) {
if (reason.length == 0) {
revert TransferToNonERC721ReceiverImplementer();
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
}
/**
* @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
* And also called before burning one token.
*
* startTokenId - the first token id to be transferred
* quantity - the amount to be transferred
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, `tokenId` will be burned by `from`.
* - `from` and `to` are never both zero.
*/
function _beforeTokenTransfers(
address from,
address to,
uint256 startTokenId,
uint256 quantity
) internal virtual {}
/**
* @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
* minting.
* And also called after one token has been burned.
*
* startTokenId - the first token id to be transferred
* quantity - the amount to be transferred
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
* transferred to `to`.
* - When `from` is zero, `tokenId` has been minted for `to`.
* - When `to` is zero, `tokenId` has been burned by `from`.
* - `from` and `to` are never both zero.
*/
function _afterTokenTransfers(
address from,
address to,
uint256 startTokenId,
uint256 quantity
) internal virtual {}
/**
* @dev Returns the message sender (defaults to `msg.sender`).
*
* If you are writing GSN compatible contracts, you need to override this function.
*/
function _msgSenderERC721A() internal view virtual returns (address) {
return msg.sender;
}
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/
function _toString(uint256 value)
internal
pure
returns (string memory ptr)
{
assembly {
// The maximum value of a uint256 contains 78 digits (1 byte per digit),
// but we allocate 128 bytes to keep the free memory pointer 32-byte word aliged.
// We will need 1 32-byte word to store the length,
// and 3 32-byte words to store a maximum of 78 digits. Total: 32 + 3 * 32 = 128.
ptr := add(mload(0x40), 128)
// Update the free memory pointer to allocate.
mstore(0x40, ptr)
// Cache the end of the memory to calculate the length later.
let end := ptr
// We write the string from the rightmost digit to the leftmost digit.
// The following is essentially a do-while loop that also handles the zero case.
// Costs a bit more than early returning for the zero case,
// but cheaper in terms of deployment and overall runtime costs.
for {
// Initialize and perform the first pass without check.
let temp := value
// Move the pointer 1 byte leftwards to point to an empty character slot.
ptr := sub(ptr, 1)
// Write the character to the pointer. 48 is the ASCII index of '0'.
mstore8(ptr, add(48, mod(temp, 10)))
temp := div(temp, 10)
} temp {
// Keep dividing `temp` until zero.
temp := div(temp, 10)
} {
// Body of the for loop.
ptr := sub(ptr, 1)
mstore8(ptr, add(48, mod(temp, 10)))
}
let length := sub(end, ptr)
// Move the pointer 32 bytes leftwards to make room for the length.
ptr := sub(ptr, 32)
// Store the length.
mstore(ptr, length)
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
pragma solidity ^0.8.0;
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
abstract contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor() {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and making it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_transferOwnership(_msgSender());
}
/**
* @dev 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 {
_transferOwnership(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 amount
) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
// ERC721A Contracts v3.3.0
// Creator: Chiru Labs
pragma solidity ^0.8.7;
/**
* @dev Interface of an ERC721A compliant contract.
*/
interface IERC721A {
/**
* The caller must own the token or be an approved operator.
*/
error ApprovalCallerNotOwnerNorApproved();
/**
* The token does not exist.
*/
error ApprovalQueryForNonexistentToken();
/**
* The caller cannot approve to their own address.
*/
error ApproveToCaller();
/**
* The caller cannot approve to the current owner.
*/
error ApprovalToCurrentOwner();
/**
* Cannot query the balance for the zero address.
*/
error BalanceQueryForZeroAddress();
/**
* Cannot mint to the zero address.
*/
error MintToZeroAddress();
/**
* The quantity of tokens minted must be more than zero.
*/
error MintZeroQuantity();
/**
* The token does not exist.
*/
error OwnerQueryForNonexistentToken();
/**
* The caller must own the token or be an approved operator.
*/
error TransferCallerNotOwnerNorApproved();
/**
* The token must be owned by `from`.
*/
error TransferFromIncorrectOwner();
/**
* Cannot safely transfer to a contract that does not implement the ERC721Receiver interface.
*/
error TransferToNonERC721ReceiverImplementer();
/**
* Cannot transfer to the zero address.
*/
error TransferToZeroAddress();
/**
* The token does not exist.
*/
error URIQueryForNonexistentToken();
struct TokenOwnership {
// The address of the owner.
address addr;
// Keeps track of the start time of ownership with minimal overhead for tokenomics.
uint64 startTimestamp;
// Whether the token has been burned.
bool burned;
}
/**
* @dev Returns the total amount of tokens stored by the contract.
*
* Burned tokens are calculated here, use `_totalMinted()` if you want to count just minted tokens.
*/
function totalSupply() external view returns (uint256);
// ==============================
// 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);
// ==============================
// IERC721
// ==============================
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/
event Transfer(
address indexed from,
address indexed to,
uint256 indexed tokenId
);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/
event Approval(
address indexed owner,
address indexed approved,
uint256 indexed tokenId
);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/
event ApprovalForAll(
address indexed owner,
address indexed operator,
bool approved
);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/
function balanceOf(address owner) external view returns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function ownerOf(uint256 tokenId) external view returns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes calldata data
) external;
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must 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 Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/
function setApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId)
external
view
returns (address operator);
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/
function isApprovedForAll(address owner, address operator)
external
view
returns (bool);
// ==============================
// IERC721Metadata
// ==============================
/**
* @dev Returns the token collection name.
*/
function name() external view returns (string memory);
/**
* @dev Returns the token collection symbol.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
*/
function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}