pragma solidity ^0.5.0;
/**
* @title IERC165
* @dev https://eips.ethereum.org/EIPS/eip-165
*/
interface IERC165 {
/**
* @notice Query if a contract implements an interface
* @param interfaceId The interface identifier, as specified in ERC-165
* @dev Interface identification is specified in ERC-165. This function
* uses less than 30,000 gas.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
/**
* @title ERC721 Non-Fungible Token Standard basic interface
* @dev see https://eips.ethereum.org/EIPS/eip-721
*/
contract IERC721 is IERC165 {
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
function balanceOf(address owner) public view returns (uint256 balance);
function ownerOf(uint256 tokenId) public view returns (address owner);
function approve(address to, uint256 tokenId) public;
function getApproved(uint256 tokenId) public view returns (address operator);
function setApprovalForAll(address operator, bool _approved) public;
function isApprovedForAll(address owner, address operator) public view returns (bool);
function transferFrom(address from, address to, uint256 tokenId) public;
function safeTransferFrom(address from, address to, uint256 tokenId) public;
function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data) public;
}
/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/
contract IERC721Receiver {
/**
* @notice Handle the receipt of an NFT
* @dev The ERC721 smart contract calls this function on the recipient
* after a `safeTransfer`. This function MUST return the function selector,
* otherwise the caller will revert the transaction. The selector to be
* returned can be obtained as `this.onERC721Received.selector`. This
* function MAY throw to revert and reject the transfer.
* Note: the ERC721 contract address is always the message sender.
* @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 bytes4 `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
*/
function onERC721Received(address operator, address from, uint256 tokenId, bytes memory data)
public returns (bytes4);
}
/**
* @title SafeMath
* @dev Unsigned math operations with safety checks that revert on error.
*/
library SafeMath {
/**
* @dev Multiplies two unsigned integers, reverts on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// 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-solidity/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b);
return c;
}
/**
* @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a);
uint256 c = a - b;
return c;
}
/**
* @dev Adds two unsigned integers, reverts on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a);
return c;
}
/**
* @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
* reverts when dividing by zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b != 0);
return a % b;
}
}
/**
* Utility library of inline functions on addresses
*/
library Address {
/**
* Returns whether the target address is a contract
* @dev This function will return false if invoked during the constructor of a contract,
* as the code is not actually created until after the constructor finishes.
* @param account address of the account to check
* @return whether the target address is a contract
*/
function isContract(address account) internal view returns (bool) {
uint256 size;
// XXX Currently there is no better way to check if there is a contract in an address
// than to check the size of the code at that address.
// See https://ethereum.stackexchange.com/a/14016/36603
// for more details about how this works.
// TODO Check this again before the Serenity release, because all addresses will be
// contracts then.
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
}
/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented or decremented by one. 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;`
* Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the SafeMath
* overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
* directly accessed.
*/
library Counters {
using SafeMath for uint256;
struct Counter {
// 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/4637
uint256 _value; // default: 0
}
function current(Counter storage counter) internal view returns (uint256) {
return counter._value;
}
function increment(Counter storage counter) internal {
counter._value += 1;
}
function decrement(Counter storage counter) internal {
counter._value = counter._value.sub(1);
}
}
/**
* @title ERC165
* @author Matt Condon (@shrugs)
* @dev Implements ERC165 using a lookup table.
*/
contract ERC165 is IERC165 {
/*
* bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
*/
bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
/**
* @dev Mapping of interface ids to whether or not it's supported.
*/
mapping(bytes4 => bool) private _supportedInterfaces;
/**
* @dev A contract implementing SupportsInterfaceWithLookup
* implements ERC165 itself.
*/
constructor () internal {
_registerInterface(_INTERFACE_ID_ERC165);
}
/**
* @dev Implement supportsInterface(bytes4) using a lookup table.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool) {
return _supportedInterfaces[interfaceId];
}
/**
* @dev Internal method for registering an interface.
*/
function _registerInterface(bytes4 interfaceId) internal {
require(interfaceId != 0xffffffff);
_supportedInterfaces[interfaceId] = true;
}
}
/**
* @title ERC721 Non-Fungible Token Standard basic implementation
* @dev see https://eips.ethereum.org/EIPS/eip-721
*/
contract ERC721 is ERC165, IERC721 {
using SafeMath for uint256;
using Address for address;
using Counters for Counters.Counter;
// Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
// which can be also obtained as `IERC721Receiver(0).onERC721Received.selector`
bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;
// Mapping from token ID to owner
mapping (uint256 => address) private _tokenOwner;
// Mapping from token ID to approved address
mapping (uint256 => address) private _tokenApprovals;
// Mapping from owner to number of owned token
mapping (address => Counters.Counter) private _ownedTokensCount;
// Mapping from owner to operator approvals
mapping (address => mapping (address => bool)) private _operatorApprovals;
/*
* bytes4(keccak256('balanceOf(address)')) == 0x70a08231
* bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e
* bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3
* bytes4(keccak256('getApproved(uint256)')) == 0x081812fc
* bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
* bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c
* bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd
* bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e
* bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde
*
* => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^
* 0xa22cb465 ^ 0xe985e9c ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd
*/
bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd;
constructor () public {
// register the supported interfaces to conform to ERC721 via ERC165
_registerInterface(_INTERFACE_ID_ERC721);
}
/**
* @dev Gets the balance of the specified address.
* @param owner address to query the balance of
* @return uint256 representing the amount owned by the passed address
*/
function balanceOf(address owner) public view returns (uint256) {
require(owner != address(0));
return _ownedTokensCount[owner].current();
}
/**
* @dev Gets the owner of the specified token ID.
* @param tokenId uint256 ID of the token to query the owner of
* @return address currently marked as the owner of the given token ID
*/
function ownerOf(uint256 tokenId) public view returns (address) {
address owner = _tokenOwner[tokenId];
require(owner != address(0));
return owner;
}
/**
* @dev Approves another address to transfer the given token ID
* The zero address indicates there is no approved address.
* There can only be one approved address per token at a given time.
* Can only be called by the token owner or an approved operator.
* @param to address to be approved for the given token ID
* @param tokenId uint256 ID of the token to be approved
*/
function approve(address to, uint256 tokenId) public {
address owner = ownerOf(tokenId);
require(to != owner);
require(msg.sender == owner || isApprovedForAll(owner, msg.sender));
_tokenApprovals[tokenId] = to;
emit Approval(owner, to, tokenId);
}
/**
* @dev Gets the approved address for a token ID, or zero if no address set
* Reverts if the token ID does not exist.
* @param tokenId uint256 ID of the token to query the approval of
* @return address currently approved for the given token ID
*/
function getApproved(uint256 tokenId) public view returns (address) {
require(_exists(tokenId));
return _tokenApprovals[tokenId];
}
/**
* @dev Sets or unsets the approval of a given operator
* An operator is allowed to transfer all tokens of the sender on their behalf.
* @param to operator address to set the approval
* @param approved representing the status of the approval to be set
*/
function setApprovalForAll(address to, bool approved) public {
require(to != msg.sender);
_operatorApprovals[msg.sender][to] = approved;
emit ApprovalForAll(msg.sender, to, approved);
}
/**
* @dev Tells whether an operator is approved by a given owner.
* @param owner owner address which you want to query the approval of
* @param operator operator address which you want to query the approval of
* @return bool whether the given operator is approved by the given owner
*/
function isApprovedForAll(address owner, address operator) public view returns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev Transfers the ownership of a given token ID to another address.
* Usage of this method is discouraged, use `safeTransferFrom` whenever possible.
* Requires the msg.sender to be the owner, approved, or operator.
* @param from current owner of the token
* @param to address to receive the ownership of the given token ID
* @param tokenId uint256 ID of the token to be transferred
*/
function transferFrom(address from, address to, uint256 tokenId) public {
require(_isApprovedOrOwner(msg.sender, tokenId));
_transferFrom(from, to, tokenId);
}
/**
* @dev Safely transfers the ownership of a given token ID to another address
* If the target address is a contract, it must implement `onERC721Received`,
* which is called upon a safe transfer, and return the magic value
* `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`; otherwise,
* the transfer is reverted.
* Requires the msg.sender to be the owner, approved, or operator
* @param from current owner of the token
* @param to address to receive the ownership of the given token ID
* @param tokenId uint256 ID of the token to be transferred
*/
function safeTransferFrom(address from, address to, uint256 tokenId) public {
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev Safely transfers the ownership of a given token ID to another address
* If the target address is a contract, it must implement `onERC721Received`,
* which is called upon a safe transfer, and return the magic value
* `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`; otherwise,
* the transfer is reverted.
* Requires the msg.sender to be the owner, approved, or operator
* @param from current owner of the token
* @param to address to receive the ownership of the given token ID
* @param tokenId uint256 ID of the token to be transferred
* @param _data bytes data to send along with a safe transfer check
*/
function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public {
transferFrom(from, to, tokenId);
require(_checkOnERC721Received(from, to, tokenId, _data));
}
/**
* @dev Returns whether the specified token exists.
* @param tokenId uint256 ID of the token to query the existence of
* @return bool whether the token exists
*/
function _exists(uint256 tokenId) internal view returns (bool) {
address owner = _tokenOwner[tokenId];
return owner != address(0);
}
/**
* @dev Returns whether the given spender can transfer a given token ID.
* @param spender address of the spender to query
* @param tokenId uint256 ID of the token to be transferred
* @return bool whether the msg.sender is approved for the given token ID,
* is an operator of the owner, or is the owner of the token
*/
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view returns (bool) {
address owner = ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
}
/**
* @dev Internal function to mint a new token.
* Reverts if the given token ID already exists.
* @param to The address that will own the minted token
* @param tokenId uint256 ID of the token to be minted
*/
function _mint(address to, uint256 tokenId) internal {
require(to != address(0));
require(!_exists(tokenId));
_tokenOwner[tokenId] = to;
_ownedTokensCount[to].increment();
emit Transfer(address(0), to, tokenId);
}
/**
* @dev Internal function to burn a specific token.
* Reverts if the token does not exist.
* Deprecated, use _burn(uint256) instead.
* @param owner owner of the token to burn
* @param tokenId uint256 ID of the token being burned
*/
function _burn(address owner, uint256 tokenId) internal {
require(ownerOf(tokenId) == owner);
_clearApproval(tokenId);
_ownedTokensCount[owner].decrement();
_tokenOwner[tokenId] = address(0);
emit Transfer(owner, address(0), tokenId);
}
/**
* @dev Internal function to burn a specific token.
* Reverts if the token does not exist.
* @param tokenId uint256 ID of the token being burned
*/
function _burn(uint256 tokenId) internal {
_burn(ownerOf(tokenId), tokenId);
}
/**
* @dev Internal function to transfer ownership of a given token ID to another address.
* As opposed to transferFrom, this imposes no restrictions on msg.sender.
* @param from current owner of the token
* @param to address to receive the ownership of the given token ID
* @param tokenId uint256 ID of the token to be transferred
*/
function _transferFrom(address from, address to, uint256 tokenId) internal {
require(ownerOf(tokenId) == from);
require(to != address(0));
_clearApproval(tokenId);
_ownedTokensCount[from].decrement();
_ownedTokensCount[to].increment();
_tokenOwner[tokenId] = to;
emit Transfer(from, to, tokenId);
}
/**
* @dev Internal function to invoke `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(address from, address to, uint256 tokenId, bytes memory _data)
internal returns (bool)
{
if (!to.isContract()) {
return true;
}
bytes4 retval = IERC721Receiver(to).onERC721Received(msg.sender, from, tokenId, _data);
return (retval == _ERC721_RECEIVED);
}
/**
* @dev Private function to clear current approval of a given token ID.
* @param tokenId uint256 ID of the token to be transferred
*/
function _clearApproval(uint256 tokenId) private {
if (_tokenApprovals[tokenId] != address(0)) {
_tokenApprovals[tokenId] = address(0);
}
}
}
/**
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
contract IERC721Enumerable is IERC721 {
function totalSupply() public view returns (uint256);
function tokenOfOwnerByIndex(address owner, uint256 index) public view returns (uint256 tokenId);
function tokenByIndex(uint256 index) public view returns (uint256);
}
/**
* @title ERC-721 Non-Fungible Token with optional enumeration extension logic
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
contract ERC721Enumerable is ERC165, ERC721, IERC721Enumerable {
// Mapping from owner to list of owned token IDs
mapping(address => uint256[]) private _ownedTokens;
// Mapping from token ID to index of the owner tokens list
mapping(uint256 => uint256) private _ownedTokensIndex;
// Array with all token ids, used for enumeration
uint256[] private _allTokens;
// Mapping from token id to position in the allTokens array
mapping(uint256 => uint256) private _allTokensIndex;
/*
* bytes4(keccak256('totalSupply()')) == 0x18160ddd
* bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59
* bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7
*
* => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63
*/
bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63;
/**
* @dev Constructor function.
*/
constructor () public {
// register the supported interface to conform to ERC721Enumerable via ERC165
_registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);
}
/**
* @dev Gets the token ID at a given index of the tokens list of the requested owner.
* @param owner address owning the tokens list to be accessed
* @param index uint256 representing the index to be accessed of the requested tokens list
* @return uint256 token ID at the given index of the tokens list owned by the requested address
*/
function tokenOfOwnerByIndex(address owner, uint256 index) public view returns (uint256) {
require(index < balanceOf(owner));
return _ownedTokens[owner][index];
}
/**
* @dev Gets the total amount of tokens stored by the contract.
* @return uint256 representing the total amount of tokens
*/
function totalSupply() public view returns (uint256) {
return _allTokens.length;
}
/**
* @dev Gets the token ID at a given index of all the tokens in this contract
* Reverts if the index is greater or equal to the total number of tokens.
* @param index uint256 representing the index to be accessed of the tokens list
* @return uint256 token ID at the given index of the tokens list
*/
function tokenByIndex(uint256 index) public view returns (uint256) {
require(index < totalSupply());
return _allTokens[index];
}
/**
* @dev Internal function to transfer ownership of a given token ID to another address.
* As opposed to transferFrom, this imposes no restrictions on msg.sender.
* @param from current owner of the token
* @param to address to receive the ownership of the given token ID
* @param tokenId uint256 ID of the token to be transferred
*/
function _transferFrom(address from, address to, uint256 tokenId) internal {
super._transferFrom(from, to, tokenId);
_removeTokenFromOwnerEnumeration(from, tokenId);
_addTokenToOwnerEnumeration(to, tokenId);
}
/**
* @dev Internal function to mint a new token.
* Reverts if the given token ID already exists.
* @param to address the beneficiary that will own the minted token
* @param tokenId uint256 ID of the token to be minted
*/
function _mint(address to, uint256 tokenId) internal {
super._mint(to, tokenId);
_addTokenToOwnerEnumeration(to, tokenId);
_addTokenToAllTokensEnumeration(tokenId);
}
/**
* @dev Internal function to burn a specific token.
* Reverts if the token does not exist.
* Deprecated, use _burn(uint256) instead.
* @param owner owner of the token to burn
* @param tokenId uint256 ID of the token being burned
*/
function _burn(address owner, uint256 tokenId) internal {
super._burn(owner, tokenId);
_removeTokenFromOwnerEnumeration(owner, tokenId);
// Since tokenId will be deleted, we can clear its slot in _ownedTokensIndex to trigger a gas refund
_ownedTokensIndex[tokenId] = 0;
_removeTokenFromAllTokensEnumeration(tokenId);
}
/**
* @dev Gets the list of token IDs of the requested owner.
* @param owner address owning the tokens
* @return uint256[] List of token IDs owned by the requested address
*/
function _tokensOfOwner(address owner) internal view returns (uint256[] storage) {
return _ownedTokens[owner];
}
/**
* @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 {
_ownedTokensIndex[tokenId] = _ownedTokens[to].length;
_ownedTokens[to].push(tokenId);
}
/**
* @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(address from, 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 = _ownedTokens[from].length.sub(1);
uint256 tokenIndex = _ownedTokensIndex[tokenId];
// When the token to delete is the last token, the swap operation is unnecessary
if (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 array
_ownedTokens[from].length--;
// Note that _ownedTokensIndex[tokenId] hasn't been cleared: it still points to the old slot (now occupied by
// lastTokenId, or just over the end of the array if the token was the last one).
}
/**
* @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.sub(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 array
_allTokens.length--;
_allTokensIndex[tokenId] = 0;
}
}
/**
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
contract IERC721Metadata is IERC721 {
function name() external view returns (string memory);
function symbol() external view returns (string memory);
function tokenURI(uint256 tokenId) external view returns (string memory);
}
contract ERC721Metadata is ERC165, ERC721, IERC721Metadata {
// Token name
string private _name;
// Token symbol
string private _symbol;
// Optional mapping for token URIs
mapping(uint256 => string) private _tokenURIs;
/*
* bytes4(keccak256('name()')) == 0x06fdde03
* bytes4(keccak256('symbol()')) == 0x95d89b41
* bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd
*
* => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f
*/
bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f;
/**
* @dev Constructor function
*/
constructor (string memory name, string memory symbol) public {
_name = name;
_symbol = symbol;
// register the supported interfaces to conform to ERC721 via ERC165
_registerInterface(_INTERFACE_ID_ERC721_METADATA);
}
/**
* @dev Gets the token name.
* @return string representing the token name
*/
function name() external view returns (string memory) {
return _name;
}
/**
* @dev Gets the token symbol.
* @return string representing the token symbol
*/
function symbol() external view returns (string memory) {
return _symbol;
}
/**
* @dev Returns an URI for a given token ID.
* Throws if the token ID does not exist. May return an empty string.
* @param tokenId uint256 ID of the token to query
*/
function tokenURI(uint256 tokenId) external view returns (string memory) {
require(_exists(tokenId));
return _tokenURIs[tokenId];
}
/**
* @dev Internal function to set the token URI for a given token.
* Reverts if the token ID does not exist.
* @param tokenId uint256 ID of the token to set its URI
* @param uri string URI to assign
*/
function _setTokenURI(uint256 tokenId, string memory uri) internal {
require(_exists(tokenId));
_tokenURIs[tokenId] = uri;
}
/**
* @dev Internal function to burn a specific token.
* Reverts if the token does not exist.
* Deprecated, use _burn(uint256) instead.
* @param owner owner of the token to burn
* @param tokenId uint256 ID of the token being burned by the msg.sender
*/
function _burn(address owner, uint256 tokenId) internal {
super._burn(owner, tokenId);
// Clear metadata (if any)
if (bytes(_tokenURIs[tokenId]).length != 0) {
delete _tokenURIs[tokenId];
}
}
}
/**
* @title Full ERC721 Token
* This implementation includes all the required and some optional functionality of the ERC721 standard
* Moreover, it includes approve all functionality using operator terminology
* @dev see https://eips.ethereum.org/EIPS/eip-721
*/
contract ERC721Full is ERC721, ERC721Enumerable, ERC721Metadata {
constructor (string memory name, string memory symbol) public ERC721Metadata(name, symbol) {
// solhint-disable-previous-line no-empty-blocks
}
}
/**
* @title Roles
* @dev Library for managing addresses assigned to a Role.
*/
library Roles {
struct Role {
mapping (address => bool) bearer;
}
/**
* @dev Give an account access to this role.
*/
function add(Role storage role, address account) internal {
require(!has(role, account));
role.bearer[account] = true;
}
/**
* @dev Remove an account's access to this role.
*/
function remove(Role storage role, address account) internal {
require(has(role, account));
role.bearer[account] = false;
}
/**
* @dev Check if an account has this role.
* @return bool
*/
function has(Role storage role, address account) internal view returns (bool) {
require(account != address(0));
return role.bearer[account];
}
}
contract Governable {
using Roles for Roles.Role;
event GovernorAdded(address indexed account);
event GovernorRemoved(address indexed account);
Roles.Role private _governors;
constructor () internal {
_addGovernor(msg.sender);
}
modifier onlyGovernor() {
require(isGovernor(msg.sender));
_;
}
function isGovernor(address account) public view returns (bool) {
return _governors.has(account);
}
function addGovernor(address account) public onlyGovernor {
_addGovernor(account);
}
function renounceGovernor() public {
_removeGovernor(msg.sender);
}
function _addGovernor(address account) internal {
_governors.add(account);
emit GovernorAdded(account);
}
function _removeGovernor(address account) internal {
_governors.remove(account);
emit GovernorRemoved(account);
}
}
/**
* @title ERC721MetadataMintable
* @dev ERC721 minting logic with metadata.
*/
contract ERC721MetadataMintable is ERC721, ERC721Metadata, Governable {
/**
* @dev Function to mint tokens.
* @param to The address that will receive the minted tokens.
* @param tokenId The token id to mint.
* @param tokenURI The token URI of the minted token.
* @return A boolean that indicates if the operation was successful.
*/
function mint(address to, uint256 tokenId, string memory tokenURI)
public
onlyGovernor
returns (bool)
{
_mint(to, tokenId);
_setTokenURI(tokenId, tokenURI);
return true;
}
}
/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
*/
contract Ownable {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender
* account.
*/
constructor () internal {
_owner = msg.sender;
emit OwnershipTransferred(address(0), _owner);
}
/**
* @return the address of the owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(isOwner(), "Ownable: caller is not the owner");
_;
}
/**
* @return true if `msg.sender` is the owner of the contract.
*/
function isOwner() public view returns (bool) {
return msg.sender == _owner;
}
/**
* @dev Allows the current owner to relinquish control of the contract.
* It will not be possible to call the functions with the `onlyOwner`
* modifier anymore.
* @notice Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Allows the current owner to transfer control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/
function transferOwnership(address newOwner) public onlyOwner {
_transferOwnership(newOwner);
}
/**
* @dev Transfers control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
contract ERC721Classic is
ERC721Full,
ERC721MetadataMintable,
Ownable
{
constructor(string memory name, string memory symbol)
public
ERC721Full(name, symbol)
Ownable()
{} // solium-disable-line
}
{
"compilationTarget": {
"ERC721Classic.sol": "ERC721Classic"
},
"evmVersion": "petersburg",
"libraries": {},
"optimizer": {
"enabled": true,
"runs": 200
},
"remappings": []
}
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