// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)pragmasolidity ^0.8.1;/**
* @dev Collection of functions related to the address type
*/libraryAddress{
/**
* @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.
* ====
*/functionisContract(address account) internalviewreturns (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].
*/functionsendValue(addresspayable 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._
*/functionfunctionCall(address target, bytesmemory data) internalreturns (bytesmemory) {
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._
*/functionfunctionCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
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._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value
) internalreturns (bytesmemory) {
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._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(address(this).balance>= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytesmemory 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._
*/functionfunctionStaticCall(address target, bytesmemory data) internalviewreturns (bytesmemory) {
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._
*/functionfunctionStaticCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalviewreturns (bytesmemory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytesmemory 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._
*/functionfunctionDelegateCall(address target, bytesmemory data) internalreturns (bytesmemory) {
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._
*/functionfunctionDelegateCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytesmemory 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._
*/functionverifyCallResult(bool success,
bytesmemory returndata,
stringmemory errorMessage
) internalpurereturns (bytesmemory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if presentif (returndata.length>0) {
// The easiest way to bubble the revert reason is using memory via assemblyassembly {
let returndata_size :=mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)pragmasolidity ^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.
*/abstractcontractContext{
function_msgSender() internalviewvirtualreturns (address) {
returnmsg.sender;
}
function_msgData() internalviewvirtualreturns (bytescalldata) {
returnmsg.data;
}
}
Contract Source Code
File 4 of 26: Counters.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Counters.sol)pragmasolidity ^0.8.0;/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
*/libraryCounters{
structCounter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add// this feature: see https://github.com/ethereum/solidity/issues/4637uint256 _value; // default: 0
}
functioncurrent(Counter storage counter) internalviewreturns (uint256) {
return counter._value;
}
functionincrement(Counter storage counter) internal{
unchecked {
counter._value +=1;
}
}
functiondecrement(Counter storage counter) internal{
uint256 value = counter._value;
require(value >0, "Counter: decrement overflow");
unchecked {
counter._value = value -1;
}
}
functionreset(Counter storage counter) internal{
counter._value =0;
}
}
Contract Source Code
File 5 of 26: ERC165.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)pragmasolidity ^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.
*/abstractcontractERC165isIERC165{
/**
* @dev See {IERC165-supportsInterface}.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverridereturns (bool) {
return interfaceId ==type(IERC165).interfaceId;
}
}
Contract Source Code
File 6 of 26: ERC721.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/ERC721.sol)pragmasolidity ^0.8.0;import"./IERC721.sol";
import"./IERC721Receiver.sol";
import"./extensions/IERC721Metadata.sol";
import"../../utils/Address.sol";
import"../../utils/Context.sol";
import"../../utils/Strings.sol";
import"../../utils/introspection/ERC165.sol";
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata extension, but not including the Enumerable extension, which is available separately as
* {ERC721Enumerable}.
*/contractERC721isContext, ERC165, IERC721, IERC721Metadata{
usingAddressforaddress;
usingStringsforuint256;
// Token namestringprivate _name;
// Token symbolstringprivate _symbol;
// Mapping from token ID to owner addressmapping(uint256=>address) private _owners;
// Mapping owner address to token countmapping(address=>uint256) private _balances;
// Mapping from token ID to approved addressmapping(uint256=>address) private _tokenApprovals;
// Mapping from owner to operator approvalsmapping(address=>mapping(address=>bool)) private _operatorApprovals;
/**
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
*/constructor(stringmemory name_, stringmemory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev See {IERC165-supportsInterface}.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverride(ERC165, IERC165) returns (bool) {
return
interfaceId ==type(IERC721).interfaceId||
interfaceId ==type(IERC721Metadata).interfaceId||super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721-balanceOf}.
*/functionbalanceOf(address owner) publicviewvirtualoverridereturns (uint256) {
require(owner !=address(0), "ERC721: balance query for the zero address");
return _balances[owner];
}
/**
* @dev See {IERC721-ownerOf}.
*/functionownerOf(uint256 tokenId) publicviewvirtualoverridereturns (address) {
address owner = _owners[tokenId];
require(owner !=address(0), "ERC721: owner query for nonexistent token");
return owner;
}
/**
* @dev See {IERC721Metadata-name}.
*/functionname() publicviewvirtualoverridereturns (stringmemory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/functionsymbol() publicviewvirtualoverridereturns (stringmemory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/functiontokenURI(uint256 tokenId) publicviewvirtualoverridereturns (stringmemory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
stringmemory baseURI = _baseURI();
returnbytes(baseURI).length>0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
}
/**
* @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
* token will be the concatenation of the `baseURI` and the `tokenId`. Empty
* by default, can be overriden in child contracts.
*/function_baseURI() internalviewvirtualreturns (stringmemory) {
return"";
}
/**
* @dev See {IERC721-approve}.
*/functionapprove(address to, uint256 tokenId) publicvirtualoverride{
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}.
*/functiongetApproved(uint256 tokenId) publicviewvirtualoverridereturns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/functionsetApprovalForAll(address operator, bool approved) publicvirtualoverride{
_setApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/functionisApprovedForAll(address owner, address operator) publicviewvirtualoverridereturns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/functiontransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
//solhint-disable-next-line max-line-lengthrequire(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) publicvirtualoverride{
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(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) internalvirtual{
_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) internalviewvirtualreturns (bool) {
return _owners[tokenId] !=address(0);
}
/**
* @dev Returns whether `spender` is allowed to manage `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/function_isApprovedOrOwner(address spender, uint256 tokenId) internalviewvirtualreturns (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, uint256 tokenId) internalvirtual{
_safeMint(to, tokenId, "");
}
/**
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
*/function_safeMint(address to,
uint256 tokenId,
bytesmemory _data
) internalvirtual{
_mint(to, tokenId);
require(
_checkOnERC721Received(address(0), to, tokenId, _data),
"ERC721: transfer to non ERC721Receiver implementer"
);
}
/**
* @dev Mints `tokenId` and transfers it to `to`.
*
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
*
* Requirements:
*
* - `tokenId` must not exist.
* - `to` cannot be the zero address.
*
* Emits a {Transfer} event.
*/function_mint(address to, uint256 tokenId) internalvirtual{
require(to !=address(0), "ERC721: mint to the zero address");
require(!_exists(tokenId), "ERC721: token already minted");
_beforeTokenTransfer(address(0), to, tokenId);
_balances[to] +=1;
_owners[tokenId] = to;
emit Transfer(address(0), to, tokenId);
_afterTokenTransfer(address(0), to, tokenId);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/function_burn(uint256 tokenId) internalvirtual{
address owner = ERC721.ownerOf(tokenId);
_beforeTokenTransfer(owner, address(0), tokenId);
// Clear approvals
_approve(address(0), tokenId);
_balances[owner] -=1;
delete _owners[tokenId];
emit Transfer(owner, address(0), tokenId);
_afterTokenTransfer(owner, address(0), tokenId);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/function_transfer(addressfrom,
address to,
uint256 tokenId
) internalvirtual{
require(ERC721.ownerOf(tokenId) ==from, "ERC721: transfer from incorrect owner");
require(to !=address(0), "ERC721: transfer to the zero address");
_beforeTokenTransfer(from, to, tokenId);
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_balances[from] -=1;
_balances[to] +=1;
_owners[tokenId] = to;
emit Transfer(from, to, tokenId);
_afterTokenTransfer(from, to, tokenId);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/function_approve(address to, uint256 tokenId) internalvirtual{
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
}
/**
* @dev Approve `operator` to operate on all of `owner` tokens
*
* Emits a {ApprovalForAll} event.
*/function_setApprovalForAll(address owner,
address operator,
bool approved
) internalvirtual{
require(owner != operator, "ERC721: approve to caller");
_operatorApprovals[owner][operator] = approved;
emit ApprovalForAll(owner, operator, approved);
}
/**
* @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(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) privatereturns (bool) {
if (to.isContract()) {
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
return retval == IERC721Receiver.onERC721Received.selector;
} catch (bytesmemory reason) {
if (reason.length==0) {
revert("ERC721: transfer to non ERC721Receiver implementer");
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
} else {
returntrue;
}
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/function_beforeTokenTransfer(addressfrom,
address to,
uint256 tokenId
) internalvirtual{}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/function_afterTokenTransfer(addressfrom,
address to,
uint256 tokenId
) internalvirtual{}
}
Contract Source Code
File 7 of 26: ERC721A.sol
// SPDX-License-Identifier: MIT// Creator: Chiru Labspragmasolidity ^0.8.4;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/token/ERC721/extensions/IERC721Enumerable.sol";
import"@openzeppelin/contracts/utils/Address.sol";
import"@openzeppelin/contracts/utils/Context.sol";
import"@openzeppelin/contracts/utils/Strings.sol";
import"@openzeppelin/contracts/utils/introspection/ERC165.sol";
errorApprovalCallerNotOwnerNorApproved();
errorApprovalQueryForNonexistentToken();
errorApproveToCaller();
errorApprovalToCurrentOwner();
errorBalanceQueryForZeroAddress();
errorMintedQueryForZeroAddress();
errorMintToZeroAddress();
errorMintZeroQuantity();
errorOwnerIndexOutOfBounds();
errorOwnerQueryForNonexistentToken();
errorTokenIndexOutOfBounds();
errorTransferCallerNotOwnerNorApproved();
errorTransferFromIncorrectOwner();
errorTransferToNonERC721ReceiverImplementer();
errorTransferToZeroAddress();
errorUnableDetermineTokenOwner();
errorURIQueryForNonexistentToken();
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata and Enumerable extension. Built to optimize for lower gas during batch mints.
*
* Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
*
* Does not support burning tokens to address(0).
*
* Assumes that an owner cannot have more than the 2**128 - 1 (max value of uint128) of supply
*/contractERC721AisContext,
ERC165,
IERC721,
IERC721Metadata,
IERC721Enumerable{
usingAddressforaddress;
usingStringsforuint256;
structTokenOwnership {
address addr;
uint64 startTimestamp;
}
structAddressData {
uint128 balance;
uint128 numberMinted;
}
uint256internal _currentIndex;
// Token namestringprivate _name;
// Token symbolstringprivate _symbol;
// Mapping from token ID to ownership details// An empty struct value does not necessarily mean the token is unowned. See ownershipOf implementation for details.mapping(uint256=> TokenOwnership) internal _ownerships;
// Mapping owner address to address datamapping(address=> AddressData) private _addressData;
// Mapping from token ID to approved addressmapping(uint256=>address) private _tokenApprovals;
// Mapping from owner to operator approvalsmapping(address=>mapping(address=>bool)) private _operatorApprovals;
constructor(stringmemory name_, stringmemory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev See {IERC721Enumerable-totalSupply}.
*/functiontotalSupply() publicviewoverridereturns (uint256) {
return _currentIndex;
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/functiontokenByIndex(uint256 index)
publicviewoverridereturns (uint256)
{
if (index >= totalSupply()) revert TokenIndexOutOfBounds();
return index;
}
/**
* @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
* This read function is O(totalSupply). If calling from a separate contract, be sure to test gas first.
* It may also degrade with extremely large collection sizes (e.g >> 10000), test for your use case.
*/functiontokenOfOwnerByIndex(address owner, uint256 index)
publicviewoverridereturns (uint256)
{
if (index >= balanceOf(owner)) revert OwnerIndexOutOfBounds();
uint256 numMintedSoFar = totalSupply();
uint256 tokenIdsIdx;
address currOwnershipAddr;
// Counter overflow is impossible as the loop breaks when uint256 i is equal to another uint256 numMintedSoFar.unchecked {
for (uint256 i; i < numMintedSoFar; i++) {
TokenOwnership memory ownership = _ownerships[i];
if (ownership.addr !=address(0)) {
currOwnershipAddr = ownership.addr;
}
if (currOwnershipAddr == owner) {
if (tokenIdsIdx == index) {
return i;
}
tokenIdsIdx++;
}
}
}
// Execution should never reach this point.assert(false);
}
/**
* @dev See {IERC165-supportsInterface}.
*/functionsupportsInterface(bytes4 interfaceId)
publicviewvirtualoverride(ERC165, IERC165)
returns (bool)
{
return
interfaceId ==type(IERC721).interfaceId||
interfaceId ==type(IERC721Metadata).interfaceId||
interfaceId ==type(IERC721Enumerable).interfaceId||super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721-balanceOf}.
*/functionbalanceOf(address owner) publicviewoverridereturns (uint256) {
if (owner ==address(0)) revert BalanceQueryForZeroAddress();
returnuint256(_addressData[owner].balance);
}
function_numberMinted(address owner) internalviewreturns (uint256) {
if (owner ==address(0)) revert MintedQueryForZeroAddress();
returnuint256(_addressData[owner].numberMinted);
}
/**
* 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.
*/functionownershipOf(uint256 tokenId)
internalviewreturns (TokenOwnership memory)
{
if (!_exists(tokenId)) revert OwnerQueryForNonexistentToken();
unchecked {
for (uint256 curr = tokenId; ; curr--) {
TokenOwnership memory ownership = _ownerships[curr];
if (ownership.addr !=address(0)) {
return ownership;
}
}
}
}
/**
* @dev See {IERC721-ownerOf}.
*/functionownerOf(uint256 tokenId) publicviewoverridereturns (address) {
return ownershipOf(tokenId).addr;
}
/**
* @dev See {IERC721Metadata-name}.
*/functionname() publicviewvirtualoverridereturns (stringmemory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/functionsymbol() publicviewvirtualoverridereturns (stringmemory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/functiontokenURI(uint256 tokenId)
publicviewvirtualoverridereturns (stringmemory)
{
if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
stringmemory baseURI = _baseURI();
returnbytes(baseURI).length!=0
? string(abi.encodePacked(baseURI, tokenId.toString()))
: "";
}
/**
* @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
* token will be the concatenation of the `baseURI` and the `tokenId`. Empty
* by default, can be overriden in child contracts.
*/function_baseURI() internalviewvirtualreturns (stringmemory) {
return"";
}
/**
* @dev See {IERC721-approve}.
*/functionapprove(address to, uint256 tokenId) publicoverride{
address owner = ERC721A.ownerOf(tokenId);
if (to == owner) revert ApprovalToCurrentOwner();
if (_msgSender() != owner &&!isApprovedForAll(owner, _msgSender()))
revert ApprovalCallerNotOwnerNorApproved();
_approve(to, tokenId, owner);
}
/**
* @dev See {IERC721-getApproved}.
*/functiongetApproved(uint256 tokenId)
publicviewoverridereturns (address)
{
if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/functionsetApprovalForAll(address operator, bool approved)
publicoverride{
if (operator == _msgSender()) revert ApproveToCaller();
_operatorApprovals[_msgSender()][operator] = approved;
emit ApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/functionisApprovedForAll(address owner, address operator)
publicviewvirtualoverridereturns (bool)
{
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/functiontransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) publicoverride{
_transfer(from, to, tokenId);
if (!_checkOnERC721Received(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) internalviewreturns (bool) {
return tokenId < _currentIndex;
}
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,
bytesmemory _data
) internal{
_mint(to, quantity, _data, true);
}
/**
* @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,
bytesmemory _data,
bool safe
) 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 > 3.4e38 (2**128) - 1// updatedIndex overflows if _currentIndex + quantity > 1.56e77 (2**256) - 1unchecked {
_addressData[to].balance+=uint128(quantity);
_addressData[to].numberMinted +=uint128(quantity);
_ownerships[startTokenId].addr = to;
_ownerships[startTokenId].startTimestamp =uint64(block.timestamp);
uint256 updatedIndex = startTokenId;
for (uint256 i; i < quantity; i++) {
emit Transfer(address(0), to, updatedIndex);
if (
safe &&!_checkOnERC721Received(address(0), to, updatedIndex, _data)
) {
revert TransferToNonERC721ReceiverImplementer();
}
updatedIndex++;
}
_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(addressfrom,
address to,
uint256 tokenId
) private{
TokenOwnership memory prevOwnership = ownershipOf(tokenId);
bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
getApproved(tokenId) == _msgSender() ||
isApprovedForAll(prevOwnership.addr, _msgSender()));
if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
if (prevOwnership.addr !=from) revert TransferFromIncorrectOwner();
if (to ==address(0)) revert TransferToZeroAddress();
_beforeTokenTransfers(from, to, tokenId, 1);
// Clear approvals from the previous owner
_approve(address(0), tokenId, prevOwnership.addr);
// 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 {
_addressData[from].balance-=1;
_addressData[to].balance+=1;
_ownerships[tokenId].addr = to;
_ownerships[tokenId].startTimestamp =uint64(block.timestamp);
// If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.// Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.uint256 nextTokenId = tokenId +1;
if (_ownerships[nextTokenId].addr ==address(0)) {
if (_exists(nextTokenId)) {
_ownerships[nextTokenId].addr = prevOwnership.addr;
_ownerships[nextTokenId].startTimestamp = prevOwnership
.startTimestamp;
}
}
}
emit Transfer(from, to, tokenId);
_afterTokenTransfers(from, to, tokenId, 1);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/function_approve(address to,
uint256 tokenId,
address owner
) private{
_tokenApprovals[tokenId] = to;
emit Approval(owner, 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(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) privatereturns (bool) {
if (to.isContract()) {
try
IERC721Receiver(to).onERC721Received(
_msgSender(),
from,
tokenId,
_data
)
returns (bytes4 retval) {
return retval == IERC721Receiver(to).onERC721Received.selector;
} catch (bytesmemory reason) {
if (reason.length==0)
revert TransferToNonERC721ReceiverImplementer();
else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
} else {
returntrue;
}
}
/**
* @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
*
* 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`.
*/function_beforeTokenTransfers(addressfrom,
address to,
uint256 startTokenId,
uint256 quantity
) internalvirtual{}
/**
* @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
* minting.
*
* 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` and `to` are never both zero.
*/function_afterTokenTransfers(addressfrom,
address to,
uint256 startTokenId,
uint256 quantity
) internalvirtual{}
}
Contract Source Code
File 8 of 26: ERC721Enumerable.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)pragmasolidity ^0.8.0;import"../ERC721.sol";
import"./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.
*/abstractcontractERC721EnumerableisERC721, IERC721Enumerable{
// Mapping from owner to list of owned token IDsmapping(address=>mapping(uint256=>uint256)) private _ownedTokens;
// Mapping from token ID to index of the owner tokens listmapping(uint256=>uint256) private _ownedTokensIndex;
// Array with all token ids, used for enumerationuint256[] private _allTokens;
// Mapping from token id to position in the allTokens arraymapping(uint256=>uint256) private _allTokensIndex;
/**
* @dev See {IERC165-supportsInterface}.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverride(IERC165, ERC721) returns (bool) {
return interfaceId ==type(IERC721Enumerable).interfaceId||super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
*/functiontokenOfOwnerByIndex(address owner, uint256 index) publicviewvirtualoverridereturns (uint256) {
require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
return _ownedTokens[owner][index];
}
/**
* @dev See {IERC721Enumerable-totalSupply}.
*/functiontotalSupply() publicviewvirtualoverridereturns (uint256) {
return _allTokens.length;
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/functiontokenByIndex(uint256 index) publicviewvirtualoverridereturns (uint256) {
require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
return _allTokens[index];
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` will be burned.
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/function_beforeTokenTransfer(addressfrom,
address to,
uint256 tokenId
) internalvirtualoverride{
super._beforeTokenTransfer(from, to, tokenId);
if (from==address(0)) {
_addTokenToAllTokensEnumeration(tokenId);
} elseif (from!= to) {
_removeTokenFromOwnerEnumeration(from, tokenId);
}
if (to ==address(0)) {
_removeTokenFromAllTokensEnumeration(tokenId);
} elseif (to !=from) {
_addTokenToOwnerEnumeration(to, tokenId);
}
}
/**
* @dev Private function to add a token to this extension's ownership-tracking data structures.
* @param to address representing the new owner of the given token ID
* @param tokenId uint256 ID of the token to be added to the tokens list of the given address
*/function_addTokenToOwnerEnumeration(address to, uint256 tokenId) private{
uint256 length = ERC721.balanceOf(to);
_ownedTokens[to][length] = tokenId;
_ownedTokensIndex[tokenId] = length;
}
/**
* @dev Private function to add a token to this extension's token tracking data structures.
* @param tokenId uint256 ID of the token to be added to the tokens list
*/function_addTokenToAllTokensEnumeration(uint256 tokenId) private{
_allTokensIndex[tokenId] = _allTokens.length;
_allTokens.push(tokenId);
}
/**
* @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
* while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
* gas optimizations e.g. when performing a transfer operation (avoiding double writes).
* This has O(1) time complexity, but alters the order of the _ownedTokens array.
* @param from address representing the previous owner of the given token ID
* @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
*/function_removeTokenFromOwnerEnumeration(addressfrom, uint256 tokenId) private{
// To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and// then delete the last slot (swap and pop).uint256 lastTokenIndex = ERC721.balanceOf(from) -1;
uint256 tokenIndex = _ownedTokensIndex[tokenId];
// When the token to delete is the last token, the swap operation is unnecessaryif (tokenIndex != lastTokenIndex) {
uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];
_ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
_ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
}
// This also deletes the contents at the last position of the arraydelete _ownedTokensIndex[tokenId];
delete _ownedTokens[from][lastTokenIndex];
}
/**
* @dev Private function to remove a token from this extension's token tracking data structures.
* This has O(1) time complexity, but alters the order of the _allTokens array.
* @param tokenId uint256 ID of the token to be removed from the tokens list
*/function_removeTokenFromAllTokensEnumeration(uint256 tokenId) private{
// To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and// then delete the last slot (swap and pop).uint256 lastTokenIndex = _allTokens.length-1;
uint256 tokenIndex = _allTokensIndex[tokenId];
// When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so// rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding// an 'if' statement (like in _removeTokenFromOwnerEnumeration)uint256 lastTokenId = _allTokens[lastTokenIndex];
_allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
_allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index// This also deletes the contents at the last position of the arraydelete _allTokensIndex[tokenId];
_allTokens.pop();
}
}
Contract Source Code
File 9 of 26: IERC165.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)pragmasolidity ^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}.
*/interfaceIERC165{
/**
* @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.
*/functionsupportsInterface(bytes4 interfaceId) externalviewreturns (bool);
}
Contract Source Code
File 10 of 26: IERC20.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)pragmasolidity ^0.8.0;/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/interfaceIERC20{
/**
* @dev Returns the amount of tokens in existence.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/functionbalanceOf(address account) externalviewreturns (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.
*/functiontransfer(address to, uint256 amount) externalreturns (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.
*/functionallowance(address owner, address spender) externalviewreturns (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.
*/functionapprove(address spender, uint256 amount) externalreturns (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.
*/functiontransferFrom(addressfrom,
address to,
uint256 amount
) externalreturns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/eventTransfer(addressindexedfrom, addressindexed 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.
*/eventApproval(addressindexed owner, addressindexed spender, uint256 value);
}
Contract Source Code
File 11 of 26: IERC721.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)pragmasolidity ^0.8.0;import"../../utils/introspection/IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/interfaceIERC721isIERC165{
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/eventTransfer(addressindexedfrom, addressindexed to, uint256indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/eventApproval(addressindexed owner, addressindexed approved, uint256indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/eventApprovalForAll(addressindexed owner, addressindexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/functionbalanceOf(address owner) externalviewreturns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functionownerOf(uint256 tokenId) externalviewreturns (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.
*/functionsafeTransferFrom(addressfrom,
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.
*/functiontransferFrom(addressfrom,
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.
*/functionapprove(address to, uint256 tokenId) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functiongetApproved(uint256 tokenId) externalviewreturns (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.
*/functionsetApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/functionisApprovedForAll(address owner, address operator) externalviewreturns (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.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytescalldata data
) external;
}
Contract Source Code
File 12 of 26: IERC721Enumerable.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)pragmasolidity ^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
*/interfaceIERC721EnumerableisIERC721{
/**
* @dev Returns the total amount of tokens stored by the contract.
*/functiontotalSupply() externalviewreturns (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.
*/functiontokenOfOwnerByIndex(address owner, uint256 index) externalviewreturns (uint256);
/**
* @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.
*/functiontokenByIndex(uint256 index) externalviewreturns (uint256);
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)pragmasolidity ^0.8.0;/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/interfaceIERC721Receiver{
/**
* @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`.
*/functiononERC721Received(address operator,
addressfrom,
uint256 tokenId,
bytescalldata data
) externalreturns (bytes4);
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/MerkleProof.sol)pragmasolidity ^0.8.0;/**
* @dev These functions deal with verification of Merkle Trees proofs.
*
* The proofs can be generated using the JavaScript library
* https://github.com/miguelmota/merkletreejs[merkletreejs].
* Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
*
* See `test/utils/cryptography/MerkleProof.test.js` for some examples.
*/libraryMerkleProof{
/**
* @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*/functionverify(bytes32[] memory proof,
bytes32 root,
bytes32 leaf
) internalpurereturns (bool) {
return processProof(proof, leaf) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* _Available since v4.4._
*/functionprocessProof(bytes32[] memory proof, bytes32 leaf) internalpurereturns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i =0; i < proof.length; i++) {
bytes32 proofElement = proof[i];
if (computedHash <= proofElement) {
// Hash(current computed hash + current element of the proof)
computedHash = _efficientHash(computedHash, proofElement);
} else {
// Hash(current element of the proof + current computed hash)
computedHash = _efficientHash(proofElement, computedHash);
}
}
return computedHash;
}
function_efficientHash(bytes32 a, bytes32 b) privatepurereturns (bytes32 value) {
assembly {
mstore(0x00, a)
mstore(0x20, b)
value :=keccak256(0x00, 0x40)
}
}
}
Contract Source Code
File 21 of 26: Ownable.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)pragmasolidity ^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.
*/abstractcontractOwnableisContext{
addressprivate _owner;
eventOwnershipTransferred(addressindexed previousOwner, addressindexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/constructor() {
_transferOwnership(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/functionowner() publicviewvirtualreturns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/modifieronlyOwner() {
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.
*/functionrenounceOwnership() publicvirtualonlyOwner{
_transferOwnership(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/functiontransferOwnership(address newOwner) publicvirtualonlyOwner{
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) internalvirtual{
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
Contract Source Code
File 22 of 26: ReentrancyGuard.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)pragmasolidity ^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].
*/abstractcontractReentrancyGuard{
// 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.uint256privateconstant _NOT_ENTERED =1;
uint256privateconstant _ENTERED =2;
uint256private _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.
*/modifiernonReentrant() {
// On the first call to nonReentrant, _notEntered will be truerequire(_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;
}
}
Contract Source Code
File 23 of 26: SafeERC20.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)pragmasolidity ^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.
*/librarySafeERC20{
usingAddressforaddress;
functionsafeTransfer(
IERC20 token,
address to,
uint256 value
) internal{
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
functionsafeTransferFrom(
IERC20 token,
addressfrom,
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.
*/functionsafeApprove(
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));
}
functionsafeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal{
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
functionsafeDecreaseAllowance(
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, bytesmemory 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.bytesmemory returndata =address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length>0) {
// Return data is optionalrequire(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
Contract Source Code
File 24 of 26: Strings.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)pragmasolidity ^0.8.0;/**
* @dev String operations.
*/libraryStrings{
bytes16privateconstant _HEX_SYMBOLS ="0123456789abcdef";
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/functiontoString(uint256 value) internalpurereturns (stringmemory) {
// Inspired by OraclizeAPI's implementation - MIT licence// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.solif (value ==0) {
return"0";
}
uint256 temp = value;
uint256 digits;
while (temp !=0) {
digits++;
temp /=10;
}
bytesmemory buffer =newbytes(digits);
while (value !=0) {
digits -=1;
buffer[digits] =bytes1(uint8(48+uint256(value %10)));
value /=10;
}
returnstring(buffer);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/functiontoHexString(uint256 value) internalpurereturns (stringmemory) {
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.
*/functiontoHexString(uint256 value, uint256 length) internalpurereturns (stringmemory) {
bytesmemory buffer =newbytes(2* length +2);
buffer[0] ="0";
buffer[1] ="x";
for (uint256 i =2* length +1; i >1; --i) {
buffer[i] = _HEX_SYMBOLS[value &0xf];
value >>=4;
}
require(value ==0, "Strings: hex length insufficient");
returnstring(buffer);
}
}
Contract Source Code
File 25 of 26: VRFConsumerBase.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.8.0;import"./interfaces/LinkTokenInterface.sol";
import"./VRFRequestIDBase.sol";
/** ****************************************************************************
* @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.
* *****************************************************************************
* @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 constuctor(<other arguments>, address _vrfCoordinator, address _link)
* @dev VRFConsumerBase(_vrfCoordinator, _link) 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), and have told you the minimum LINK
* @dev price for VRF service. Make sure your contract has sufficient LINK, and
* @dev call requestRandomness(keyHash, fee, seed), where seed is the input you
* @dev want to generate randomness from.
*
* @dev Once the VRFCoordinator has received and validated the oracle's response
* @dev to your request, it will call your contract's fulfillRandomness method.
*
* @dev The randomness argument to fulfillRandomness is the actual random value
* @dev generated from your seed.
*
* @dev The requestId argument is generated from the keyHash and the seed by
* @dev makeRequestId(keyHash, seed). If your contract could have concurrent
* @dev requests open, you can use the requestId to track which seed is
* @dev associated with which randomness. See VRFRequestIDBase.sol for more
* @dev details. (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. (Which is critical to making unpredictable randomness! See the
* @dev next section.)
*
* *****************************************************************************
* @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 ultimate input to the VRF is mixed with the block hash of the
* @dev block in which the request is made, user-provided seeds have no impact
* @dev on its economic security properties. They are only included for API
* @dev compatability with previous versions of this contract.
*
* @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.
*/abstractcontractVRFConsumerBaseisVRFRequestIDBase{
/**
* @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 VRFConsumerBase 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 randomness the VRF output
*/functionfulfillRandomness(bytes32 requestId, uint256 randomness) internalvirtual;
/**
* @dev In order to keep backwards compatibility we have kept the user
* seed field around. We remove the use of it because given that the blockhash
* enters later, it overrides whatever randomness the used seed provides.
* Given that it adds no security, and can easily lead to misunderstandings,
* we have removed it from usage and can now provide a simpler API.
*/uint256privateconstant USER_SEED_PLACEHOLDER =0;
/**
* @notice requestRandomness initiates a request for VRF output given _seed
*
* @dev The fulfillRandomness method receives the output, once it's provided
* @dev by the Oracle, and verified by the vrfCoordinator.
*
* @dev The _keyHash must already be registered with the VRFCoordinator, and
* @dev the _fee must exceed the fee specified during registration of the
* @dev _keyHash.
*
* @dev The _seed parameter is vestigial, and is kept only for API
* @dev compatibility with older versions. It can't *hurt* to mix in some of
* @dev your own randomness, here, but it's not necessary because the VRF
* @dev oracle will mix the hash of the block containing your request into the
* @dev VRF seed it ultimately uses.
*
* @param _keyHash ID of public key against which randomness is generated
* @param _fee The amount of LINK to send with the request
*
* @return requestId unique ID for this request
*
* @dev The returned requestId can be used to distinguish responses to
* @dev concurrent requests. It is passed as the first argument to
* @dev fulfillRandomness.
*/functionrequestRandomness(bytes32 _keyHash, uint256 _fee) internalreturns (bytes32 requestId) {
LINK.transferAndCall(vrfCoordinator, _fee, abi.encode(_keyHash, USER_SEED_PLACEHOLDER));
// This is the seed passed to VRFCoordinator. The oracle will mix this with// the hash of the block containing this request to obtain the seed/input// which is finally passed to the VRF cryptographic machinery.uint256 vRFSeed = makeVRFInputSeed(_keyHash, USER_SEED_PLACEHOLDER, address(this), nonces[_keyHash]);
// nonces[_keyHash] must stay in sync with// VRFCoordinator.nonces[_keyHash][this], which was incremented by the above// successful LINK.transferAndCall (in VRFCoordinator.randomnessRequest).// This provides protection against the user repeating their input seed,// which would result in a predictable/duplicate output, if multiple such// requests appeared in the same block.
nonces[_keyHash] = nonces[_keyHash] +1;
return makeRequestId(_keyHash, vRFSeed);
}
LinkTokenInterface internalimmutable LINK;
addressprivateimmutable vrfCoordinator;
// Nonces for each VRF key from which randomness has been requested.//// Must stay in sync with VRFCoordinator[_keyHash][this]mapping(bytes32=>uint256) /* keyHash *//* nonce */private nonces;
/**
* @param _vrfCoordinator address of VRFCoordinator contract
* @param _link address of LINK token contract
*
* @dev https://docs.chain.link/docs/link-token-contracts
*/constructor(address _vrfCoordinator, address _link) {
vrfCoordinator = _vrfCoordinator;
LINK = LinkTokenInterface(_link);
}
// rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF// proof. rawFulfillRandomness then calls fulfillRandomness, after validating// the origin of the callfunctionrawFulfillRandomness(bytes32 requestId, uint256 randomness) external{
require(msg.sender== vrfCoordinator, "Only VRFCoordinator can fulfill");
fulfillRandomness(requestId, randomness);
}
}
Contract Source Code
File 26 of 26: VRFRequestIDBase.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.8.0;contractVRFRequestIDBase{
/**
* @notice returns the seed which is actually input to the VRF coordinator
*
* @dev To prevent repetition of VRF output due to repetition of the
* @dev user-supplied seed, that seed is combined in a hash with the
* @dev user-specific nonce, and the address of the consuming contract. The
* @dev risk of repetition is mostly mitigated by inclusion of a blockhash in
* @dev the final seed, but the nonce does protect against repetition in
* @dev requests which are included in a single block.
*
* @param _userSeed VRF seed input provided by user
* @param _requester Address of the requesting contract
* @param _nonce User-specific nonce at the time of the request
*/functionmakeVRFInputSeed(bytes32 _keyHash,
uint256 _userSeed,
address _requester,
uint256 _nonce
) internalpurereturns (uint256) {
returnuint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
}
/**
* @notice Returns the id for this request
* @param _keyHash The serviceAgreement ID to be used for this request
* @param _vRFInputSeed The seed to be passed directly to the VRF
* @return The id for this request
*
* @dev Note that _vRFInputSeed is not the seed passed by the consuming
* @dev contract, but the one generated by makeVRFInputSeed
*/functionmakeRequestId(bytes32 _keyHash, uint256 _vRFInputSeed) internalpurereturns (bytes32) {
returnkeccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
}
}