mirror of
https://github.com/sharkdp/bat
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376 lines
13 KiB
Solidity
Vendored
376 lines
13 KiB
Solidity
Vendored
// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.0;
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import "./IERC721.sol";
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import "./IERC721Receiver.sol";
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import "./extensions/IERC721Metadata.sol";
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import "../../utils/Address.sol";
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import "../../utils/Context.sol";
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import "../../utils/Strings.sol";
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import "../../utils/introspection/ERC165.sol";
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/**
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* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
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* the Metadata extension, but not including the Enumerable extension, which is available separately as
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* {ERC721Enumerable}.
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*/
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contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
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using Address for address;
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using Strings for uint256;
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// Token name
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string private _name;
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// Token symbol
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string private _symbol;
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// Mapping from token ID to owner address
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mapping (uint256 => address) private _owners;
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// Mapping owner address to token count
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mapping (address => uint256) private _balances;
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// Mapping from token ID to approved address
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mapping (uint256 => address) private _tokenApprovals;
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// Mapping from owner to operator approvals
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mapping (address => mapping (address => bool)) private _operatorApprovals;
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/**
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* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
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*/
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constructor (string memory name_, string memory symbol_) {
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_name = name_;
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_symbol = symbol_;
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}
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/**
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* @dev See {IERC165-supportsInterface}.
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*/
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function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
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return interfaceId == type(IERC721).interfaceId
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|| interfaceId == type(IERC721Metadata).interfaceId
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|| super.supportsInterface(interfaceId);
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}
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/**
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* @dev See {IERC721-balanceOf}.
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*/
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function balanceOf(address owner) public view virtual override returns (uint256) {
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require(owner != address(0), "ERC721: balance query for the zero address");
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return _balances[owner];
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}
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/**
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* @dev See {IERC721-ownerOf}.
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*/
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function ownerOf(uint256 tokenId) public view virtual override returns (address) {
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address owner = _owners[tokenId];
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require(owner != address(0), "ERC721: owner query for nonexistent token");
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return owner;
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}
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/**
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* @dev See {IERC721Metadata-name}.
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*/
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function name() public view virtual override returns (string memory) {
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return _name;
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}
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/**
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* @dev See {IERC721Metadata-symbol}.
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*/
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function symbol() public view virtual override returns (string memory) {
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return _symbol;
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}
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/**
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* @dev See {IERC721Metadata-tokenURI}.
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*/
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function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
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require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
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string memory baseURI = _baseURI();
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return bytes(baseURI).length > 0
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? string(abi.encodePacked(baseURI, tokenId.toString()))
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: '';
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}
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/**
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* @dev Base URI for computing {tokenURI}. Empty by default, can be overriden
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* in child contracts.
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*/
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function _baseURI() internal view virtual returns (string memory) {
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return "";
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}
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/**
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* @dev See {IERC721-approve}.
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*/
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function approve(address to, uint256 tokenId) public virtual override {
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address owner = ERC721.ownerOf(tokenId);
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require(to != owner, "ERC721: approval to current owner");
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require(_msgSender() == owner || isApprovedForAll(owner, _msgSender()),
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"ERC721: approve caller is not owner nor approved for all"
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);
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_approve(to, tokenId);
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}
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/**
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* @dev See {IERC721-getApproved}.
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*/
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function getApproved(uint256 tokenId) public view virtual override returns (address) {
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require(_exists(tokenId), "ERC721: approved query for nonexistent token");
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return _tokenApprovals[tokenId];
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}
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/**
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* @dev See {IERC721-setApprovalForAll}.
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*/
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function setApprovalForAll(address operator, bool approved) public virtual override {
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require(operator != _msgSender(), "ERC721: approve to caller");
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_operatorApprovals[_msgSender()][operator] = approved;
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emit ApprovalForAll(_msgSender(), operator, approved);
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}
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/**
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* @dev See {IERC721-isApprovedForAll}.
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*/
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function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
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return _operatorApprovals[owner][operator];
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}
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/**
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* @dev See {IERC721-transferFrom}.
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*/
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function transferFrom(address from, address to, uint256 tokenId) public virtual override {
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//solhint-disable-next-line max-line-length
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require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
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_transfer(from, to, tokenId);
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}
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/**
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* @dev See {IERC721-safeTransferFrom}.
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*/
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function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override {
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safeTransferFrom(from, to, tokenId, "");
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}
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/**
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* @dev See {IERC721-safeTransferFrom}.
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*/
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function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override {
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require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
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_safeTransfer(from, to, tokenId, _data);
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}
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/**
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* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
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* are aware of the ERC721 protocol to prevent tokens from being forever locked.
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*
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* `_data` is additional data, it has no specified format and it is sent in call to `to`.
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*
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* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
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* implement alternative mechanisms to perform token transfer, such as signature-based.
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*
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* Requirements:
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*
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* - `from` cannot be the zero address.
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* - `to` cannot be the zero address.
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* - `tokenId` token must exist and be owned by `from`.
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* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
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*
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* Emits a {Transfer} event.
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*/
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function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual {
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_transfer(from, to, tokenId);
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require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
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}
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/**
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* @dev Returns whether `tokenId` exists.
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*
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* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
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*
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* Tokens start existing when they are minted (`_mint`),
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* and stop existing when they are burned (`_burn`).
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*/
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function _exists(uint256 tokenId) internal view virtual returns (bool) {
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return _owners[tokenId] != address(0);
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}
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/**
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* @dev Returns whether `spender` is allowed to manage `tokenId`.
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*
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* Requirements:
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*
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* - `tokenId` must exist.
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*/
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function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
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require(_exists(tokenId), "ERC721: operator query for nonexistent token");
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address owner = ERC721.ownerOf(tokenId);
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return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
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}
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/**
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* @dev Safely mints `tokenId` and transfers it to `to`.
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*
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* Requirements:
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*
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* - `tokenId` must not exist.
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* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
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*
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* Emits a {Transfer} event.
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*/
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function _safeMint(address to, uint256 tokenId) internal virtual {
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_safeMint(to, tokenId, "");
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}
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/**
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* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
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* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
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*/
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function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual {
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_mint(to, tokenId);
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require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
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}
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/**
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* @dev Mints `tokenId` and transfers it to `to`.
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*
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* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
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*
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* Requirements:
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*
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* - `tokenId` must not exist.
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* - `to` cannot be the zero address.
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*
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* Emits a {Transfer} event.
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*/
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function _mint(address to, uint256 tokenId) internal virtual {
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require(to != address(0), "ERC721: mint to the zero address");
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require(!_exists(tokenId), "ERC721: token already minted");
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_beforeTokenTransfer(address(0), to, tokenId);
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_balances[to] += 1;
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_owners[tokenId] = to;
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emit Transfer(address(0), to, tokenId);
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}
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/**
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* @dev Destroys `tokenId`.
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* The approval is cleared when the token is burned.
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*
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* Requirements:
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*
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* - `tokenId` must exist.
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*
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* Emits a {Transfer} event.
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*/
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function _burn(uint256 tokenId) internal virtual {
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address owner = ERC721.ownerOf(tokenId);
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_beforeTokenTransfer(owner, address(0), tokenId);
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// Clear approvals
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_approve(address(0), tokenId);
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_balances[owner] -= 1;
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delete _owners[tokenId];
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emit Transfer(owner, address(0), tokenId);
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}
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/**
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* @dev Transfers `tokenId` from `from` to `to`.
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* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
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*
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* Requirements:
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*
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* - `to` cannot be the zero address.
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* - `tokenId` token must be owned by `from`.
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*
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* Emits a {Transfer} event.
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*/
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function _transfer(address from, address to, uint256 tokenId) internal virtual {
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require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
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require(to != address(0), "ERC721: transfer to the zero address");
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_beforeTokenTransfer(from, to, tokenId);
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// Clear approvals from the previous owner
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_approve(address(0), tokenId);
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_balances[from] -= 1;
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_balances[to] += 1;
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_owners[tokenId] = to;
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emit Transfer(from, to, tokenId);
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}
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/**
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* @dev Approve `to` to operate on `tokenId`
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*
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* Emits a {Approval} event.
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*/
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function _approve(address to, uint256 tokenId) internal virtual {
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_tokenApprovals[tokenId] = to;
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emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
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}
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/**
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* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
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* The call is not executed if the target address is not a contract.
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*
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* @param from address representing the previous owner of the given token ID
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* @param to target address that will receive the tokens
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* @param tokenId uint256 ID of the token to be transferred
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* @param _data bytes optional data to send along with the call
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* @return bool whether the call correctly returned the expected magic value
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*/
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function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)
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private returns (bool)
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{
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if (to.isContract()) {
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try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
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return retval == IERC721Receiver(to).onERC721Received.selector;
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} catch (bytes memory reason) {
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if (reason.length == 0) {
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revert("ERC721: transfer to non ERC721Receiver implementer");
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} else {
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// solhint-disable-next-line no-inline-assembly
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assembly {
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revert(add(32, reason), mload(reason))
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}
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}
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}
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} else {
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return true;
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}
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}
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/**
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* @dev Hook that is called before any token transfer. This includes minting
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* and burning.
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*
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* Calling conditions:
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*
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* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
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* transferred to `to`.
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* - When `from` is zero, `tokenId` will be minted for `to`.
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* - When `to` is zero, ``from``'s `tokenId` will be burned.
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* - `from` cannot be the zero address.
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* - `to` cannot be the zero address.
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*
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* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
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*/
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function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { }
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}
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