forked from DecentralizedClimateFoundation/DCIPs
37 lines
1.2 KiB
Solidity
37 lines
1.2 KiB
Solidity
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// SPDX-License-Identifier: CC0-1.0
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pragma solidity ^0.8.0;
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import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
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import "./IERC5008.sol";
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contract ERC5008 is ERC721, IERC5008 {
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mapping(uint256 => uint256) private _tokenNonce;
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constructor(string memory name_, string memory symbol_)ERC721(name_, symbol_){
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}
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/// @notice Get the nonce of an NFT
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/// Throws if `tokenId` is not a valid NFT
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/// @param tokenId The NFT to get the nonce for
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/// @return The nonce of this NFT
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function nonce(uint256 tokenId) public virtual override view returns(uint256) {
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require(_exists(tokenId), "Error: query for nonexistent token");
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return _tokenNonce[tokenId];
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}
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function _beforeTokenTransfer(
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address from,
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address to,
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uint256 tokenId
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) internal virtual override{
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super._beforeTokenTransfer(from, to, tokenId);
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_tokenNonce[tokenId]++;
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}
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/// @dev See {IERC165-supportsInterface}.
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function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
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return interfaceId == type(IERC5008).interfaceId || super.supportsInterface(interfaceId);
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}
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}
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