/**
*Submitted for verification at arbiscan.io on 2021-09-13
*/
// Sources flattened with hardhat v2.6.0 https://hardhat.org
// File contracts/erc721.sol
// SPDX-License-Identifier: MIT
pragma solidity 0.8.4;
/**
* @dev ERC-721 non-fungible token standard.
* See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md.
*/
interface ERC721 {
/**
* @dev Emits when ownership of any NFT changes by any mechanism. This event emits when NFTs are
* created (`from` == 0) and destroyed (`to` == 0). Exception: during contract creation, any
* number of NFTs may be created and assigned without emitting Transfer. At the time of any
* transfer, the approved address for that NFT (if any) is reset to none.
*/
event Transfer(
address indexed _from,
address indexed _to,
uint256 indexed _tokenId
);
/**
* @dev This emits when the approved address for an NFT is changed or reaffirmed. The zero
* address indicates there is no approved address. When a Transfer event emits, this also
* indicates that the approved address for that NFT (if any) is reset to none.
*/
event Approval(
address indexed _owner,
address indexed _approved,
uint256 indexed _tokenId
);
/**
* @dev This emits when an operator is enabled or disabled for an owner. The operator can manage
* all NFTs of the owner.
*/
event ApprovalForAll(
address indexed _owner,
address indexed _operator,
bool _approved
);
/**
* @notice Throws unless `msg.sender` is the current owner, an authorized operator, or the
* approved address for this NFT. Throws if `_from` is not the current owner. Throws if `_to` is
* the zero address. Throws if `_tokenId` is not a valid NFT. When transfer is complete, this
* function checks if `_to` is a smart contract (code size > 0). If so, it calls
* `onERC721Received` on `_to` and throws if the return value is not
* `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`.
* @dev Transfers the ownership of an NFT from one address to another address. This function can
* be changed to payable.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
* @param _data Additional data with no specified format, sent in call to `_to`.
*/
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId,
bytes calldata _data
) external;
/**
* @notice This works identically to the other function with an extra data parameter, except this
* function just sets data to ""
* @dev Transfers the ownership of an NFT from one address to another address. This function can
* be changed to payable.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
*/
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId
) external;
/**
* @notice The caller is responsible to confirm that `_to` is capable of receiving NFTs or else
* they may be permanently lost.
* @dev Throws unless `msg.sender` is the current owner, an authorized operator, or the approved
* address for this NFT. Throws if `_from` is not the current owner. Throws if `_to` is the zero
* address. Throws if `_tokenId` is not a valid NFT. This function can be changed to payable.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
*/
function transferFrom(
address _from,
address _to,
uint256 _tokenId
) external;
/**
* @notice The zero address indicates there is no approved address. Throws unless `msg.sender` is
* the current NFT owner, or an authorized operator of the current owner.
* @param _approved The new approved NFT controller.
* @dev Set or reaffirm the approved address for an NFT. This function can be changed to payable.
* @param _tokenId The NFT to approve.
*/
function approve(address _approved, uint256 _tokenId) external;
/**
* @notice The contract MUST allow multiple operators per owner.
* @dev Enables or disables approval for a third party ("operator") to manage all of
* `msg.sender`'s assets. It also emits the ApprovalForAll event.
* @param _operator Address to add to the set of authorized operators.
* @param _approved True if the operators is approved, false to revoke approval.
*/
function setApprovalForAll(address _operator, bool _approved) external;
/**
* @dev Returns the number of NFTs owned by `_owner`. NFTs assigned to the zero address are
* considered invalid, and this function throws for queries about the zero address.
* @notice Count all NFTs assigned to an owner.
* @param _owner Address for whom to query the balance.
* @return Balance of _owner.
*/
function balanceOf(address _owner) external view returns (uint256);
/**
* @notice Find the owner of an NFT.
* @dev Returns the address of the owner of the NFT. NFTs assigned to the zero address are
* considered invalid, and queries about them do throw.
* @param _tokenId The identifier for an NFT.
* @return Address of _tokenId owner.
*/
function ownerOf(uint256 _tokenId) external view returns (address);
/**
* @notice Throws if `_tokenId` is not a valid NFT.
* @dev Get the approved address for a single NFT.
* @param _tokenId The NFT to find the approved address for.
* @return Address that _tokenId is approved for.
*/
function getApproved(uint256 _tokenId) external view returns (address);
/**
* @notice Query if an address is an authorized operator for another address.
* @dev Returns true if `_operator` is an approved operator for `_owner`, false otherwise.
* @param _owner The address that owns the NFTs.
* @param _operator The address that acts on behalf of the owner.
* @return True if approved for all, false otherwise.
*/
function isApprovedForAll(address _owner, address _operator)
external
view
returns (bool);
}
// File contracts/erc721-token-receiver.solpragma solidity 0.8.4;
/**
* @dev ERC-721 interface for accepting safe transfers.
* See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md.
*/
interface ERC721TokenReceiver {
/**
* @notice The contract address is always the message sender. A wallet/broker/auction application
* MUST implement the wallet interface if it will accept safe transfers.
* @dev Handle the receipt of a NFT. The ERC721 smart contract calls this function on the
* recipient after a `transfer`. This function MAY throw to revert and reject the transfer. Return
* of other than the magic value MUST result in the transaction being reverted.
* Returns `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))` unless throwing.
* @param _operator The address which called `safeTransferFrom` function.
* @param _from The address which previously owned the token.
* @param _tokenId The NFT identifier which is being transferred.
* @param _data Additional data with no specified format.
* @return Returns `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`.
*/
function onERC721Received(
address _operator,
address _from,
uint256 _tokenId,
bytes calldata _data
) external returns (bytes4);
}
// File contracts/erc165.solpragma solidity 0.8.4;
/**
* @dev A standard for detecting smart contract interfaces.
* See: https://eips.ethereum.org/EIPS/eip-165.
*/
interface ERC165 {
/**
* @dev Checks if the smart contract includes a specific interface.
* This function uses less than 30,000 gas.
* @param _interfaceID The interface identifier, as specified in ERC-165.
* @return True if _interfaceID is supported, false otherwise.
*/
function supportsInterface(bytes4 _interfaceID)
external
view
returns (bool);
}
// File contracts/supports-interface.sol
pragma solidity 0.8.4;
/**
* @dev Implementation of standard for detect smart contract interfaces.
*/
contract SupportsInterface is ERC165 {
/**
* @dev Mapping of supported intefraces. You must not set element 0xffffffff to true.
*/
mapping(bytes4 => bool) internal supportedInterfaces;
/**
* @dev Contract constructor.
*/
constructor() {
supportedInterfaces[0x01ffc9a7] = true; // ERC165
}
/**
* @dev Function to check which interfaces are suported by this contract.
* @param _interfaceID Id of the interface.
* @return True if _interfaceID is supported, false otherwise.
*/
function supportsInterface(bytes4 _interfaceID)
external
view
override
returns (bool)
{
return supportedInterfaces[_interfaceID];
}
}
// File contracts/address-utils.sol
pragma solidity 0.8.4;
/**
* @notice Based on:
* https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol
* Requires EIP-1052.
* @dev Utility library of inline functions on addresses.
*/
library AddressUtils {
/**
* @dev Returns whether the target address is a contract.
* @param _addr Address to check.
* @return addressCheck True if _addr is a contract, false if not.
*/
function isContract(address _addr)
internal
view
returns (bool addressCheck)
{
// This method relies in extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
// for accounts without code, i.e. `keccak256('')`
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
assembly {
codehash := extcodehash(_addr)
} // solhint-disable-line
addressCheck = (codehash != 0x0 && codehash != accountHash);
}
}
// File contracts/nf-token.sol
pragma solidity 0.8.4;
/**
* @dev Implementation of ERC-721 non-fungible token standard.
*/
contract NFToken is ERC721, SupportsInterface {
using AddressUtils for address;
/**
* @dev List of revert message codes. Implementing dApp should handle showing the correct message.
* Based on 0xcert framework error codes.
*/
string constant ZERO_ADDRESS = '003001';
string constant NOT_VALID_NFT = '003002';
string constant NOT_OWNER_OR_OPERATOR = '003003';
string constant NOT_OWNER_APPROVED_OR_OPERATOR = '003004';
string constant NOT_ABLE_TO_RECEIVE_NFT = '003005';
string constant NFT_ALREADY_EXISTS = '003006';
string constant NOT_OWNER = '003007';
string constant IS_OWNER = '003008';
/**
* @dev Magic value of a smart contract that can receive NFT.
* Equal to: bytes4(keccak256("onERC721Received(address,address,uint256,bytes)")).
*/
bytes4 internal constant MAGIC_ON_ERC721_RECEIVED = 0x150b7a02;
/**
* @dev A mapping from NFT ID to the address that owns it.
*/
mapping(uint256 => address) internal idToOwner;
/**
* @dev Mapping from NFT ID to approved address.
*/
mapping(uint256 => address) internal idToApproval;
/**
* @dev Mapping from owner address to count of their tokens.
*/
mapping(address => uint256) private ownerToNFTokenCount;
/**
* @dev Mapping from owner address to mapping of operator addresses.
*/
mapping(address => mapping(address => bool)) internal ownerToOperators;
/**
* @dev Guarantees that the msg.sender is an owner or operator of the given NFT.
* @param _tokenId ID of the NFT to validate.
*/
modifier canOperate(uint256 _tokenId) {
address tokenOwner = idToOwner[_tokenId];
require(
tokenOwner == msg.sender ||
ownerToOperators[tokenOwner][msg.sender],
NOT_OWNER_OR_OPERATOR
);
_;
}
/**
* @dev Guarantees that the msg.sender is allowed to transfer NFT.
* @param _tokenId ID of the NFT to transfer.
*/
modifier canTransfer(uint256 _tokenId) {
address tokenOwner = idToOwner[_tokenId];
require(
tokenOwner == msg.sender ||
idToApproval[_tokenId] == msg.sender ||
ownerToOperators[tokenOwner][msg.sender],
NOT_OWNER_APPROVED_OR_OPERATOR
);
_;
}
/**
* @dev Guarantees that _tokenId is a valid Token.
* @param _tokenId ID of the NFT to validate.
*/
modifier validNFToken(uint256 _tokenId) {
require(idToOwner[_tokenId] != address(0), NOT_VALID_NFT);
_;
}
/**
* @dev Contract constructor.
*/
constructor() {
supportedInterfaces[0x80ac58cd] = true; // ERC721
}
/**
* @notice Throws unless `msg.sender` is the current owner, an authorized operator, or the
* approved address for this NFT. Throws if `_from` is not the current owner. Throws if `_to` is
* the zero address. Throws if `_tokenId` is not a valid NFT. When transfer is complete, this
* function checks if `_to` is a smart contract (code size > 0). If so, it calls
* `onERC721Received` on `_to` and throws if the return value is not
* `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`.
* @dev Transfers the ownership of an NFT from one address to another address. This function can
* be changed to payable.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
* @param _data Additional data with no specified format, sent in call to `_to`.
*/
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId,
bytes calldata _data
) external override {
_safeTransferFrom(_from, _to, _tokenId, _data);
}
/**
* @notice This works identically to the other function with an extra data parameter, except this
* function just sets data to "".
* @dev Transfers the ownership of an NFT from one address to another address. This function can
* be changed to payable.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
*/
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId
) external override {
_safeTransferFrom(_from, _to, _tokenId, '');
}
/**
* @notice The caller is responsible to confirm that `_to` is capable of receiving NFTs or else
* they may be permanently lost.
* @dev Throws unless `msg.sender` is the current owner, an authorized operator, or the approved
* address for this NFT. Throws if `_from` is not the current owner. Throws if `_to` is the zero
* address. Throws if `_tokenId` is not a valid NFT. This function can be changed to payable.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
*/
function transferFrom(
address _from,
address _to,
uint256 _tokenId
) external override canTransfer(_tokenId) validNFToken(_tokenId) {
address tokenOwner = idToOwner[_tokenId];
require(tokenOwner == _from, NOT_OWNER);
require(_to != address(0), ZERO_ADDRESS);
_transfer(_to, _tokenId);
}
/**
* @notice The zero address indicates there is no approved address. Throws unless `msg.sender` is
* the current NFT owner, or an authorized operator of the current owner.
* @dev Set or reaffirm the approved address for an NFT. This function can be changed to payable.
* @param _approved Address to be approved for the given NFT ID.
* @param _tokenId ID of the token to be approved.
*/
function approve(address _approved, uint256 _tokenId)
external
override
canOperate(_tokenId)
validNFToken(_tokenId)
{
address tokenOwner = idToOwner[_tokenId];
require(_approved != tokenOwner, IS_OWNER);
idToApproval[_tokenId] = _approved;
emit Approval(tokenOwner, _approved, _tokenId);
}
/**
* @notice This works even if sender doesn't own any tokens at the time.
* @dev Enables or disables approval for a third party ("operator") to manage all of
* `msg.sender`'s assets. It also emits the ApprovalForAll event.
* @param _operator Address to add to the set of authorized operators.
* @param _approved True if the operators is approved, false to revoke approval.
*/
function setApprovalForAll(address _operator, bool _approved)
external
override
{
ownerToOperators[msg.sender][_operator] = _approved;
emit ApprovalForAll(msg.sender, _operator, _approved);
}
/**
* @dev Returns the number of NFTs owned by `_owner`. NFTs assigned to the zero address are
* considered invalid, and this function throws for queries about the zero address.
* @param _owner Address for whom to query the balance.
* @return Balance of _owner.
*/
function balanceOf(address _owner)
external
view
override
returns (uint256)
{
require(_owner != address(0), ZERO_ADDRESS);
return _getOwnerNFTCount(_owner);
}
/**
* @dev Returns the address of the owner of the NFT. NFTs assigned to the zero address are
* considered invalid, and queries about them do throw.
* @param _tokenId The identifier for an NFT.
* @return _owner Address of _tokenId owner.
*/
function ownerOf(uint256 _tokenId)
external
view
override
returns (address _owner)
{
_owner = idToOwner[_tokenId];
require(_owner != address(0), NOT_VALID_NFT);
}
/**
* @notice Throws if `_tokenId` is not a valid NFT.
* @dev Get the approved address for a single NFT.
* @param _tokenId ID of the NFT to query the approval of.
* @return Address that _tokenId is approved for.
*/
function getApproved(uint256 _tokenId)
external
view
override
validNFToken(_tokenId)
returns (address)
{
return idToApproval[_tokenId];
}
/**
* @dev Checks if `_operator` is an approved operator for `_owner`.
* @param _owner The address that owns the NFTs.
* @param _operator The address that acts on behalf of the owner.
* @return True if approved for all, false otherwise.
*/
function isApprovedForAll(address _owner, address _operator)
external
view
override
returns (bool)
{
return ownerToOperators[_owner][_operator];
}
/**
* @notice Does NO checks.
* @dev Actually performs the transfer.
* @param _to Address of a new owner.
* @param _tokenId The NFT that is being transferred.
*/
function _transfer(address _to, uint256 _tokenId) internal {
address from = idToOwner[_tokenId];
_clearApproval(_tokenId);
_removeNFToken(from, _tokenId);
_addNFToken(_to, _tokenId);
emit Transfer(from, _to, _tokenId);
}
/**
* @notice This is an internal function which should be called from user-implemented external
* mint function. Its purpose is to show and properly initialize data structures when using this
* implementation.
* @dev Mints a new NFT.
* @param _to The address that will own the minted NFT.
* @param _tokenId of the NFT to be minted by the msg.sender.
*/
function _mint(address _to, uint256 _tokenId) internal virtual {
require(_to != address(0), ZERO_ADDRESS);
require(idToOwner[_tokenId] == address(0), NFT_ALREADY_EXISTS);
_addNFToken(_to, _tokenId);
emit Transfer(address(0), _to, _tokenId);
}
/**
* @notice This is an internal function which should be called from user-implemented external burn
* function. Its purpose is to show and properly initialize data structures when using this
* implementation. Also, note that this burn implementation allows the minter to re-mint a burned
* NFT.
* @dev Burns a NFT.
* @param _tokenId ID of the NFT to be burned.
*/
function _burn(uint256 _tokenId) internal virtual validNFToken(_tokenId) {
address tokenOwner = idToOwner[_tokenId];
_clearApproval(_tokenId);
_removeNFToken(tokenOwner, _tokenId);
emit Transfer(tokenOwner, address(0), _tokenId);
}
/**
* @notice Use and override this function with caution. Wrong usage can have serious consequences.
* @dev Removes a NFT from owner.
* @param _from Address from which we want to remove the NFT.
* @param _tokenId Which NFT we want to remove.
*/
function _removeNFToken(address _from, uint256 _tokenId) internal virtual {
require(idToOwner[_tokenId] == _from, NOT_OWNER);
ownerToNFTokenCount[_from] -= 1;
delete idToOwner[_tokenId];
}
/**
* @notice Use and override this function with caution. Wrong usage can have serious consequences.
* @dev Assigns a new NFT to owner.
* @param _to Address to which we want to add the NFT.
* @param _tokenId Which NFT we want to add.
*/
function _addNFToken(address _to, uint256 _tokenId) internal virtual {
require(idToOwner[_tokenId] == address(0), NFT_ALREADY_EXISTS);
idToOwner[_tokenId] = _to;
ownerToNFTokenCount[_to] += 1;
}
/**
* @dev Helper function that gets NFT count of owner. This is needed for overriding in enumerable
* extension to remove double storage (gas optimization) of owner NFT count.
* @param _owner Address for whom to query the count.
* @return Number of _owner NFTs.
*/
function _getOwnerNFTCount(address _owner)
internal
view
virtual
returns (uint256)
{
return ownerToNFTokenCount[_owner];
}
/**
* @dev Actually perform the safeTransferFrom.
* @param _from The current owner of the NFT.
* @param _to The new owner.
* @param _tokenId The NFT to transfer.
* @param _data Additional data with no specified format, sent in call to `_to`.
*/
function _safeTransferFrom(
address _from,
address _to,
uint256 _tokenId,
bytes memory _data
) private canTransfer(_tokenId) validNFToken(_tokenId) {
address tokenOwner = idToOwner[_tokenId];
require(tokenOwner == _from, NOT_OWNER);
require(_to != address(0), ZERO_ADDRESS);
_transfer(_to, _tokenId);
if (_to.isContract()) {
bytes4 retval = ERC721TokenReceiver(_to).onERC721Received(
msg.sender,
_from,
_tokenId,
_data
);
require(
retval == MAGIC_ON_ERC721_RECEIVED,
NOT_ABLE_TO_RECEIVE_NFT
);
}
}
/**
* @dev Clears the current approval of a given NFT ID.
* @param _tokenId ID of the NFT to be transferred.
*/
function _clearApproval(uint256 _tokenId) private {
delete idToApproval[_tokenId];
}
}
// File contracts/erc721-enumerable.solpragma solidity 0.8.4;
/**
* @dev Optional enumeration extension for ERC-721 non-fungible token standard.
* See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md.
*/
interface ERC721Enumerable {
/**
* @dev Returns a count of valid NFTs tracked by this contract, where each one of them has an
* assigned and queryable owner not equal to the zero address.
* @return Total supply of NFTs.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the token identifier for the `_index`th NFT. Sort order is not specified.
* @param _index A counter less than `totalSupply()`.
* @return Token id.
*/
function tokenByIndex(uint256 _index) external view returns (uint256);
/**
* @dev Returns the token identifier for the `_index`th NFT assigned to `_owner`. Sort order is
* not specified. It throws if `_index` >= `balanceOf(_owner)` or if `_owner` is the zero address,
* representing invalid NFTs.
* @param _owner An address where we are interested in NFTs owned by them.
* @param _index A counter less than `balanceOf(_owner)`.
* @return Token id.
*/
function tokenOfOwnerByIndex(address _owner, uint256 _index)
external
view
returns (uint256);
}
// File contracts/nf-token-enumerable.solpragma solidity 0.8.4;
/**
* @dev Optional enumeration implementation for ERC-721 non-fungible token standard.
*/
contract NFTokenEnumerable is NFToken, ERC721Enumerable {
/**
* @dev List of revert message codes. Implementing dApp should handle showing the correct message.
* Based on 0xcert framework error codes.
*/
string constant INVALID_INDEX = '005007';
/**
* @dev Array of all NFT IDs.
*/
uint256[] internal tokens;
/**
* @dev Mapping from token ID to its index in global tokens array.
*/
mapping(uint256 => uint256) internal idToIndex;
/**
* @dev Mapping from owner to list of owned NFT IDs.
*/
mapping(address => uint256[]) internal ownerToIds;
/**
* @dev Mapping from NFT ID to its index in the owner tokens list.
*/
mapping(uint256 => uint256) internal idToOwnerIndex;
/**
* @dev Contract constructor.
*/
constructor() {
supportedInterfaces[0x780e9d63] = true; // ERC721Enumerable
}
/**
* @dev Returns the count of all existing NFTokens.
* @return Total supply of NFTs.
*/
function totalSupply() external view override returns (uint256) {
return tokens.length;
}
/**
* @dev Returns NFT ID by its index.
* @param _index A counter less than `totalSupply()`.
* @return Token id.
*/
function tokenByIndex(uint256 _index)
external
view
override
returns (uint256)
{
require(_index < tokens.length, INVALID_INDEX);
return tokens[_index];
}
/**
* @dev returns the n-th NFT ID from a list of owner's tokens.
* @param _owner Token owner's address.
* @param _index Index number representing n-th token in owner's list of tokens.
* @return Token id.
*/
function tokenOfOwnerByIndex(address _owner, uint256 _index)
external
view
override
returns (uint256)
{
require(_index < ownerToIds[_owner].length, INVALID_INDEX);
return ownerToIds[_owner][_index];
}
/**
* @notice This is an internal function which should be called from user-implemented external
* mint function. Its purpose is to show and properly initialize data structures when using this
* implementation.
* @dev Mints a new NFT.
* @param _to The address that will own the minted NFT.
* @param _tokenId of the NFT to be minted by the msg.sender.
*/
function _mint(address _to, uint256 _tokenId) internal virtual override {
super._mint(_to, _tokenId);
tokens.push(_tokenId);
idToIndex[_tokenId] = tokens.length - 1;
}
/**
* @notice This is an internal function which should be called from user-implemented external
* burn function. Its purpose is to show and properly initialize data structures when using this
* implementation. Also, note that this burn implementation allows the minter to re-mint a burned
* NFT.
* @dev Burns a NFT.
* @param _tokenId ID of the NFT to be burned.
*/
function _burn(uint256 _tokenId) internal virtual override {
super._burn(_tokenId);
uint256 tokenIndex = idToIndex[_tokenId];
uint256 lastTokenIndex = tokens.length - 1;
uint256 lastToken = tokens[lastTokenIndex];
tokens[tokenIndex] = lastToken;
tokens.pop();
// This wastes gas if you are burning the last token but saves a little gas if you are not.
idToIndex[lastToken] = tokenIndex;
idToIndex[_tokenId] = 0;
}
/**
* @notice Use and override this function with caution. Wrong usage can have serious consequences.
* @dev Removes a NFT from an address.
* @param _from Address from wich we want to remove the NFT.
* @param _tokenId Which NFT we want to remove.
*/
function _removeNFToken(address _from, uint256 _tokenId)
internal
virtual
override
{
require(idToOwner[_tokenId] == _from, NOT_OWNER);
delete idToOwner[_tokenId];
uint256 tokenToRemoveIndex = idToOwnerIndex[_tokenId];
uint256 lastTokenIndex = ownerToIds[_from].length - 1;
if (lastTokenIndex != tokenToRemoveIndex) {
uint256 lastToken = ownerToIds[_from][lastTokenIndex];
ownerToIds[_from][tokenToRemoveIndex] = lastToken;
idToOwnerIndex[lastToken] = tokenToRemoveIndex;
}
ownerToIds[_from].pop();
}
/**
* @notice Use and override this function with caution. Wrong usage can have serious consequences.
* @dev Assigns a new NFT to an address.
* @param _to Address to wich we want to add the NFT.
* @param _tokenId Which NFT we want to add.
*/
function _addNFToken(address _to, uint256 _tokenId)
internal
virtual
override
{
require(idToOwner[_tokenId] == address(0), NFT_ALREADY_EXISTS);
idToOwner[_tokenId] = _to;
ownerToIds[_to].push(_tokenId);
idToOwnerIndex[_tokenId] = ownerToIds[_to].length - 1;
}
/**
* @dev Helper function that gets NFT count of owner. This is needed for overriding in enumerable
* extension to remove double storage(gas optimization) of owner NFT count.
* @param _owner Address for whom to query the count.
* @return Number of _owner NFTs.
*/
function _getOwnerNFTCount(address _owner)
internal
view
virtual
override
returns (uint256)
{
return ownerToIds[_owner].length;
}
}
// File contracts/erc721-metadata.sol
pragma solidity 0.8.4;
/**
* @dev Optional metadata extension for ERC-721 non-fungible token standard.
* See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md.
*/
interface ERC721Metadata {
/**
* @dev Returns a descriptive name for a collection of NFTs in this contract.
* @return _name Representing name.
*/
function name() external view returns (string memory _name);
/**
* @dev Returns a abbreviated name for a collection of NFTs in this contract.
* @return _symbol Representing symbol.
*/
function symbol() external view returns (string memory _symbol);
/**
* @dev Returns a distinct Uniform Resource Identifier (URI) for a given asset. It Throws if
* `_tokenId` is not a valid NFT. URIs are defined in RFC3986. The URI may point to a JSON file
* that conforms to the "ERC721 Metadata JSON Schema".
* @return URI of _tokenId.
*/
function tokenURI(uint256 _tokenId) external view returns (string memory);
}
// File contracts/nf-token-metadata.sol
pragma solidity 0.8.4;
/**
* @dev Optional metadata implementation for ERC-721 non-fungible token standard.
*/
contract NFTokenMetadata is NFToken, ERC721Metadata {
/**
* @dev A descriptive name for a collection of NFTs.
*/
string internal nftName;
/**
* @dev An abbreviated name for NFTokens.
*/
string internal nftSymbol;
/**
* @dev Mapping from NFT ID to metadata uri.
*/
mapping(uint256 => string) internal idToUri;
/**
* @notice When implementing this contract don't forget to set nftName and nftSymbol.
* @dev Contract constructor.
*/
constructor() {
supportedInterfaces[0x5b5e139f] = true; // ERC721Metadata
}
/**
* @dev Returns a descriptive name for a collection of NFTokens.
* @return _name Representing name.
*/
function name() external view override returns (string memory _name) {
_name = nftName;
}
/**
* @dev Returns an abbreviated name for NFTokens.
* @return _symbol Representing symbol.
*/
function symbol() external view override returns (string memory _symbol) {
_symbol = nftSymbol;
}
/**
* @dev A distinct URI (RFC 3986) for a given NFT.
* @param _tokenId Id for which we want uri.
* @return URI of _tokenId.
*/
function tokenURI(uint256 _tokenId)
external
view
override
validNFToken(_tokenId)
returns (string memory)
{
return idToUri[_tokenId];
}
/**
* @notice This is an internal function which should be called from user-implemented external
* burn function. Its purpose is to show and properly initialize data structures when using this
* implementation. Also, note that this burn implementation allows the minter to re-mint a burned
* NFT.
* @dev Burns a NFT.
* @param _tokenId ID of the NFT to be burned.
*/
function _burn(uint256 _tokenId) internal virtual override {
super._burn(_tokenId);
delete idToUri[_tokenId];
}
/**
* @notice This is an internal function which should be called from user-implemented external
* function. Its purpose is to show and properly initialize data structures when using this
* implementation.
* @dev Set a distinct URI (RFC 3986) for a given NFT ID.
* @param _tokenId Id for which we want URI.
* @param _uri String representing RFC 3986 URI.
*/
function _setTokenUri(uint256 _tokenId, string memory _uri)
internal
validNFToken(_tokenId)
{
idToUri[_tokenId] = _uri;
}
}
// File contracts/NFTokenMetadataEnumerable.sol
pragma solidity 0.8.4;
/**
* @dev Optional metadata implementation for ERC-721 non-fungible token standard.
*/
abstract contract NFTokenEnumerableMetadata is
NFToken,
ERC721Metadata,
ERC721Enumerable
{
/**
* @dev A descriptive name for a collection of NFTs.
*/
string internal nftName;
/**
* @dev An abbreviated name for NFTokens.
*/
string internal nftSymbol;
/**
* @dev Mapping from NFT ID to metadata uri.
*/
mapping(uint256 => string) internal idToUri;
/**
* @dev List of revert message codes. Implementing dApp should handle showing the correct message.
* Based on 0xcert framework error codes.
*/
string constant INVALID_INDEX = '005007';
/**
* @dev Array of all NFT IDs.
*/
uint256[] internal tokens;
/**
* @dev Mapping from token ID to its index in global tokens array.
*/
mapping(uint256 => uint256) internal idToIndex;
/**
* @dev Mapping from owner to list of owned NFT IDs.
*/
mapping(address => uint256[]) internal ownerToIds;
/**
* @dev Mapping from NFT ID to its index in the owner tokens list.
*/
mapping(uint256 => uint256) internal idToOwnerIndex;
/**
* @notice When implementing this contract don't forget to set nftName and nftSymbol.
* @dev Contract constructor.
*/
constructor() {
supportedInterfaces[0x780e9d63] = true; // ERC721Enumerable
supportedInterfaces[0x5b5e139f] = true; // ERC721Metadata
}
/**
* @dev Returns a descriptive name for a collection of NFTokens.
* @return _name Representing name.
*/
function name() external view override returns (string memory _name) {
_name = nftName;
}
/**
* @dev Returns an abbreviated name for NFTokens.
* @return _symbol Representing symbol.
*/
function symbol() external view override returns (string memory _symbol) {
_symbol = nftSymbol;
}
/**
* @dev A distinct URI (RFC 3986) for a given NFT.
* @param _tokenId Id for which we want uri.
* @return URI of _tokenId.
*/
function tokenURI(uint256 _tokenId)
external
view
override
validNFToken(_tokenId)
returns (string memory)
{
return idToUri[_tokenId];
}
/**
* @notice This is an internal function which should be called from user-implemented external
* function. Its purpose is to show and properly initialize data structures when using this
* implementation.
* @dev Set a distinct URI (RFC 3986) for a given NFT ID.
* @param _tokenId Id for which we want URI.
* @param _uri String representing RFC 3986 URI.
*/
function _setTokenUri(uint256 _tokenId, string memory _uri)
internal
validNFToken(_tokenId)
{
idToUri[_tokenId] = _uri;
}
/**
* @dev Returns the count of all existing NFTokens.
* @return Total supply of NFTs.
*/
function totalSupply() external view override returns (uint256) {
return tokens.length;
}
/**
* @dev Returns NFT ID by its index.
* @param _index A counter less than `totalSupply()`.
* @return Token id.
*/
function tokenByIndex(uint256 _index)
external
view
override
returns (uint256)
{
require(_index < tokens.length, INVALID_INDEX);
return tokens[_index];
}
/**
* @dev returns the n-th NFT ID from a list of owner's tokens.
* @param _owner Token owner's address.
* @param _index Index number representing n-th token in owner's list of tokens.
* @return Token id.
*/
function tokenOfOwnerByIndex(address _owner, uint256 _index)
external
view
override
returns (uint256)
{
require(_index < ownerToIds[_owner].length, INVALID_INDEX);
return ownerToIds[_owner][_index];
}
/**
* @notice This is an internal function which should be called from user-implemented external
* mint function. Its purpose is to show and properly initialize data structures when using this
* implementation.
* @dev Mints a new NFT.
* @param _to The address that will own the minted NFT.
* @param _tokenId of the NFT to be minted by the msg.sender.
*/
function _mint(address _to, uint256 _tokenId) internal virtual override {
super._mint(_to, _tokenId);
tokens.push(_tokenId);
idToIndex[_tokenId] = tokens.length - 1;
}
/**
* @notice This is an internal function which should be called from user-implemented external
* burn function. Its purpose is to show and properly initialize data structures when using this
* implementation. Also, note that this burn implementation allows the minter to re-mint a burned
* NFT.
* @dev Burns a NFT.
* @param _tokenId ID of the NFT to be burned.
*/
function _burn(uint256 _tokenId) internal virtual override {
super._burn(_tokenId);
uint256 tokenIndex = idToIndex[_tokenId];
uint256 lastTokenIndex = tokens.length - 1;
uint256 lastToken = tokens[lastTokenIndex];
tokens[tokenIndex] = lastToken;
tokens.pop();
delete idToUri[_tokenId];
// This wastes gas if you are burning the last token but saves a little gas if you are not.
idToIndex[lastToken] = tokenIndex;
idToIndex[_tokenId] = 0;
}
/**
* @notice Use and override this function with caution. Wrong usage can have serious consequences.
* @dev Removes a NFT from an address.
* @param _from Address from wich we want to remove the NFT.
* @param _tokenId Which NFT we want to remove.
*/
function _removeNFToken(address _from, uint256 _tokenId)
internal
virtual
override
{
require(idToOwner[_tokenId] == _from, NOT_OWNER);
delete idToOwner[_tokenId];
uint256 tokenToRemoveIndex = idToOwnerIndex[_tokenId];
uint256 lastTokenIndex = ownerToIds[_from].length - 1;
if (lastTokenIndex != tokenToRemoveIndex) {
uint256 lastToken = ownerToIds[_from][lastTokenIndex];
ownerToIds[_from][tokenToRemoveIndex] = lastToken;
idToOwnerIndex[lastToken] = tokenToRemoveIndex;
}
ownerToIds[_from].pop();
}
/**
* @notice Use and override this function with caution. Wrong usage can have serious consequences.
* @dev Assigns a new NFT to an address.
* @param _to Address to wich we want to add the NFT.
* @param _tokenId Which NFT we want to add.
*/
function _addNFToken(address _to, uint256 _tokenId)
internal
virtual
override
{
require(idToOwner[_tokenId] == address(0), NFT_ALREADY_EXISTS);
idToOwner[_tokenId] = _to;
ownerToIds[_to].push(_tokenId);
idToOwnerIndex[_tokenId] = ownerToIds[_to].length - 1;
}
/**
* @dev Helper function that gets NFT count of owner. This is needed for overriding in enumerable
* extension to remove double storage(gas optimization) of owner NFT count.
* @param _owner Address for whom to query the count.
* @return Number of _owner NFTs.
*/
function _getOwnerNFTs(address _owner)
internal
view
virtual
returns (uint256[] memory)
{
return ownerToIds[_owner];
}
/**
* @dev Helper function that gets NFT count of owner. This is needed for overriding in enumerable
* extension to remove double storage(gas optimization) of owner NFT count.
* @param _owner Address for whom to query the count.
* @return Number of _owner NFTs.
*/
function _getOwnerNFTCount(address _owner)
internal
view
virtual
override
returns (uint256)
{
return ownerToIds[_owner].length;
}
}
// File @openzeppelin/contracts/utils/Context.sol@v4.3.1pragma solidity 0.8.4;
/**
* @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;
}
}
// File @openzeppelin/contracts/access/Ownable.sol@v4.3.1pragma solidity 0.8.4;
/**
* @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() {
_setOwner(_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 {
_setOwner(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'
);
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// File @openzeppelin/contracts/utils/math/SafeMath.sol@v4.3.1
pragma solidity 0.8.4; // CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.
/**
* @dev Wrappers over Solidity's arithmetic operations.
*
* NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
* now has built in overflow checking.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b)
internal
pure
returns (bool, uint256)
{
unchecked {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b)
internal
pure
returns (bool, uint256)
{
unchecked {
if (b > a) return (false, 0);
return (true, a - b);
}
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b)
internal
pure
returns (bool, uint256)
{
unchecked {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b)
internal
pure
returns (bool, uint256)
{
unchecked {
if (b == 0) return (false, 0);
return (true, a / b);
}
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b)
internal
pure
returns (bool, uint256)
{
unchecked {
if (b == 0) return (false, 0);
return (true, a % b);
}
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
return a + b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
return a * b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator.
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
require(b <= a, errorMessage);
return a - b;
}
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
require(b > 0, errorMessage);
return a / b;
}
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
require(b > 0, errorMessage);
return a % b;
}
}
}
// File contracts/CeloPunks.sol
pragma solidity 0.8.4;
contract CeloPunks is NFTokenEnumerableMetadata, Ownable {
using SafeMath for uint256;
// TODO: Change the price
uint256 public price = 15 ether;
uint256 public maxSupply = 10_000;
uint256 public maxMintNFT = 15;
uint256 public royaltyFee = 2;
string public baseUri = 'https://ipfs.io/ipfs/QmWn3sCZLwyTzpT2vQL9aG9W8Uz5N2y6vaf7T2S7EFfE9s/';
mapping (uint256 => address) originalMinter;
event PriceUpdated(uint256 newPrice);
event MaxSupplyUpdated(uint256 newMaxSupply);
event BaseUriUpdated(string newBaseUri);
event royaltyFeeUpdated(uint256 royaltyFee);
// TODO: Change the name
constructor() {
nftName = 'CeloPunksTest';
nftSymbol = 'CTEST';
}
function mint() external payable {
require(msg.value >= price, 'Amount is less than price');
require(maxSupply >= this.totalSupply(), 'Sold out');
uint256 count = msg.value / price;
for (uint256 i = 0; i < count; i++) {
uint256 currentSupply = this.totalSupply();
uint256 tokenId = currentSupply;
address to = msg.sender;
super._mint(to, tokenId);
super._setTokenUri(
tokenId,
string(abi.encodePacked(baseUri, toString(tokenId), '.json'))
);
originalMinter[currentSupply] = msg.sender;
}
}
function getOwnerNFTs(address _owner)
public
view
returns (uint256[] memory)
{
return super._getOwnerNFTs(_owner);
}
function withdraw() external onlyOwner {
payable(msg.sender).transfer(address(this).balance);
}
function updatePrice(uint256 _newPrice) public onlyOwner {
price = _newPrice;
emit PriceUpdated(_newPrice);
}
function updateMaxSupply(uint256 _maxSupply) public onlyOwner {
maxSupply = _maxSupply;
emit MaxSupplyUpdated(_maxSupply);
}
function updateroyaltyFee(uint _royaltyFee) public onlyOwner {
require(_royaltyFee < 10);
royaltyFee = _royaltyFee;
emit royaltyFeeUpdated(_royaltyFee);
}
function updateBaseUri(string memory _baseUri) public onlyOwner {
baseUri = _baseUri;
emit BaseUriUpdated(_baseUri);
}
// EIP-2981
function royaltyInfo(uint256 _tokenId, uint256 _salePrice) external view
returns (address receiver, uint256 royaltyRate) {
address _receiver = originalMinter[_tokenId];
uint256 _royaltyFee = _salePrice - ((_salePrice * royaltyFee) / 100);
return(_receiver, _royaltyFee);
}
// TODO: Remove this
function destroySmartContract(address payable _to) public {
require(msg.sender == owner(), "You are not the owner");
selfdestruct(_to);
}
function toString(uint256 value) internal pure returns (string memory) {
// Inspired by OraclizeAPI's implementation - MIT license
// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
if (value == 0) {
return '0';
}
uint256 temp = value;
uint256 digits;
while (temp != 0) {
digits++;
temp /= 10;
}
bytes memory buffer = new bytes(digits);
while (value != 0) {
digits -= 1;
buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
value /= 10;
}
return string(buffer);
}
}
// File @openzeppelin/contracts/token/ERC20/IERC20.sol@v4.3.1pragma solidity 0.8.4;
/**
* @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 `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
address recipient,
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
);
}
// File @openzeppelin/contracts/utils/Address.sol@v4.3.1pragma solidity 0.8.4;
/**
* @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
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
assembly {
size := extcodesize(account)
}
return size > 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);
}
}
}
}
// File @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol@v4.3.1
pragma solidity 0.8.4;
/**
* @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'
);
}
}
}