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pragma solidity ^0.8.0; | |
// SPDX-License-Identifier: MIT | |
/** | |
* @dev Interface of the ERC165 standard, as defined in the | |
* https://eips.ethereum.org/EIPS/eip-165[EIP]. | |
* | |
* Implementers can declare support of contract interfaces, which can then be | |
* queried by others ({ERC165Checker}). | |
* | |
* For an implementation, see {ERC165}. | |
*/ | |
interface IERC165 { | |
/** | |
* @dev Returns true if this contract implements the interface defined by | |
* `interfaceId`. See the corresponding | |
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section] | |
* to learn more about how these ids are created. | |
* | |
* This function call must use less than 30 000 gas. | |
*/ | |
function supportsInterface(bytes4 interfaceId) external view returns (bool); | |
} | |
/** | |
* @dev Required interface of an ERC721 compliant contract. | |
*/ | |
interface IERC721 is IERC165 { | |
/** | |
* @dev Emitted when `tokenId` token is transferred from `from` to `to`. | |
*/ | |
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token. | |
*/ | |
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets. | |
*/ | |
event ApprovalForAll(address indexed owner, address indexed operator, bool approved); | |
/** | |
* @dev Returns the number of tokens in ``owner``'s account. | |
*/ | |
function balanceOf(address owner) external view returns (uint256 balance); | |
/** | |
* @dev Returns the owner of the `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function ownerOf(uint256 tokenId) external view returns (address owner); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Transfers `tokenId` token from `from` to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Gives permission to `to` to transfer `tokenId` token to another account. | |
* The approval is cleared when the token is transferred. | |
* | |
* Only a single account can be approved at a time, so approving the zero address clears previous approvals. | |
* | |
* Requirements: | |
* | |
* - The caller must own the token or be an approved operator. | |
* - `tokenId` must exist. | |
* | |
* Emits an {Approval} event. | |
*/ | |
function approve(address to, uint256 tokenId) external; | |
/** | |
* @dev Returns the account approved for `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function getApproved(uint256 tokenId) external view returns (address operator); | |
/** | |
* @dev Approve or remove `operator` as an operator for the caller. | |
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller. | |
* | |
* Requirements: | |
* | |
* - The `operator` cannot be the caller. | |
* | |
* Emits an {ApprovalForAll} event. | |
*/ | |
function setApprovalForAll(address operator, bool _approved) external; | |
/** | |
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`. | |
* | |
* See {setApprovalForAll} | |
*/ | |
function isApprovedForAll(address owner, address operator) external view returns (bool); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external; | |
} | |
/** | |
* @title ERC721 token receiver interface | |
* @dev Interface for any contract that wants to support safeTransfers | |
* from ERC721 asset contracts. | |
*/ | |
interface IERC721Receiver { | |
/** | |
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom} | |
* by `operator` from `from`, this function is called. | |
* | |
* It must return its Solidity selector to confirm the token transfer. | |
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted. | |
* | |
* The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`. | |
*/ | |
function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4); | |
} | |
/** | |
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension | |
* @dev See https://eips.ethereum.org/EIPS/eip-721 | |
*/ | |
interface IERC721Metadata is IERC721 { | |
/** | |
* @dev Returns the token collection name. | |
*/ | |
function name() external view returns (string memory); | |
/** | |
* @dev Returns the token collection symbol. | |
*/ | |
function symbol() external view returns (string memory); | |
/** | |
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token. | |
*/ | |
function tokenURI(uint256 tokenId) external view returns (string memory); | |
} | |
/** | |
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension | |
* @dev See https://eips.ethereum.org/EIPS/eip-721 | |
*/ | |
interface IERC721Enumerable is IERC721 { | |
/** | |
* @dev Returns the total amount of tokens stored by the contract. | |
*/ | |
function totalSupply() external view returns (uint256); | |
/** | |
* @dev Returns a token ID owned by `owner` at a given `index` of its token list. | |
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens. | |
*/ | |
function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId); | |
/** | |
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract. | |
* Use along with {totalSupply} to enumerate all tokens. | |
*/ | |
function tokenByIndex(uint256 index) external view returns (uint256); | |
} | |
abstract contract ERC165 is IERC165 { | |
/** | |
* @dev See {IERC165-supportsInterface}. | |
*/ | |
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) { | |
return interfaceId == type(IERC165).interfaceId; | |
} | |
} | |
/** | |
* @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; | |
// solhint-disable-next-line no-inline-assembly | |
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"); | |
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(bool success, bytes memory returndata) = target.delegatecall(data); | |
return _verifyCallResult(success, returndata, errorMessage); | |
} | |
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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 | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
let returndata_size := mload(returndata) | |
revert(add(32, returndata), returndata_size) | |
} | |
} else { | |
revert(errorMessage); | |
} | |
} | |
} | |
} | |
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) { | |
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) { | |
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) { | |
// 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) { | |
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) { | |
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) { | |
uint256 c = a + b; | |
require(c >= a, "SafeMath: addition overflow"); | |
return c; | |
} | |
/** | |
* @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) { | |
require(b <= a, "SafeMath: subtraction overflow"); | |
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) { | |
if (a == 0) return 0; | |
uint256 c = a * b; | |
require(c / a == b, "SafeMath: multiplication overflow"); | |
return c; | |
} | |
/** | |
* @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. 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) internal pure returns (uint256) { | |
require(b > 0, "SafeMath: division by zero"); | |
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) { | |
require(b > 0, "SafeMath: modulo by zero"); | |
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) { | |
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. | |
* | |
* CAUTION: This function is deprecated because it requires allocating memory for the error | |
* message unnecessarily. For custom revert reasons use {tryDiv}. | |
* | |
* 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) { | |
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) { | |
require(b > 0, errorMessage); | |
return a % b; | |
} | |
} | |
abstract contract Context { | |
function _msgSender() internal view virtual returns (address) { | |
return msg.sender; | |
} | |
function _msgData() internal view virtual returns (bytes calldata) { | |
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691 | |
return msg.data; | |
} | |
} | |
/** | |
* @dev String operations. | |
*/ | |
library Strings { | |
bytes16 private constant alphabet = "0123456789abcdef"; | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` decimal representation. | |
*/ | |
function toString(uint256 value) internal pure returns (string memory) { | |
// Inspired by OraclizeAPI's implementation - MIT licence | |
// 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); | |
} | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation. | |
*/ | |
function toHexString(uint256 value) internal pure returns (string memory) { | |
if (value == 0) { | |
return "0x00"; | |
} | |
uint256 temp = value; | |
uint256 length = 0; | |
while (temp != 0) { | |
length++; | |
temp >>= 8; | |
} | |
return toHexString(value, length); | |
} | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length. | |
*/ | |
function toHexString(uint256 value, uint256 length) internal pure returns (string memory) { | |
bytes memory buffer = new bytes(2 * length + 2); | |
buffer[0] = "0"; | |
buffer[1] = "x"; | |
for (uint256 i = 2 * length + 1; i > 1; --i) { | |
buffer[i] = alphabet[value & 0xf]; | |
value >>= 4; | |
} | |
require(value == 0, "Strings: hex length insufficient"); | |
return string(buffer); | |
} | |
} | |
/** | |
* @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;` | |
*/ | |
library Counters { | |
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 { | |
unchecked { | |
counter._value += 1; | |
} | |
} | |
function decrement(Counter storage counter) internal { | |
uint256 value = counter._value; | |
require(value > 0, "Counter: decrement overflow"); | |
unchecked { | |
counter._value = value - 1; | |
} | |
} | |
} | |
/** | |
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including | |
* the Metadata extension, but not including the Enumerable extension, which is available separately as | |
* {ERC721Enumerable}. | |
*/ | |
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata { | |
using Address for address; | |
using Strings for uint256; | |
// Token name | |
string private _name; | |
// Token symbol | |
string private _symbol; | |
// Mapping from token ID to owner address | |
mapping (uint256 => address) private _owners; | |
// Mapping owner address to token count | |
mapping (address => uint256) private _balances; | |
// Mapping from token ID to approved address | |
mapping (uint256 => address) private _tokenApprovals; | |
// Mapping from owner to operator approvals | |
mapping (address => mapping (address => bool)) private _operatorApprovals; | |
/** | |
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection. | |
*/ | |
constructor (string memory name_, string memory symbol_) { | |
_name = name_; | |
_symbol = symbol_; | |
} | |
/** | |
* @dev See {IERC165-supportsInterface}. | |
*/ | |
function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) { | |
return interfaceId == type(IERC721).interfaceId | |
|| interfaceId == type(IERC721Metadata).interfaceId | |
|| super.supportsInterface(interfaceId); | |
} | |
/** | |
* @dev See {IERC721-balanceOf}. | |
*/ | |
function balanceOf(address owner) public view virtual override returns (uint256) { | |
require(owner != address(0), "ERC721: balance query for the zero address"); | |
return _balances[owner]; | |
} | |
/** | |
* @dev See {IERC721-ownerOf}. | |
*/ | |
function ownerOf(uint256 tokenId) public view virtual override returns (address) { | |
address owner = _owners[tokenId]; | |
require(owner != address(0), "ERC721: owner query for nonexistent token"); | |
return owner; | |
} | |
/** | |
* @dev See {IERC721Metadata-name}. | |
*/ | |
function name() public view virtual override returns (string memory) { | |
return _name; | |
} | |
/** | |
* @dev See {IERC721Metadata-symbol}. | |
*/ | |
function symbol() public view virtual override returns (string memory) { | |
return _symbol; | |
} | |
/** | |
* @dev See {IERC721Metadata-tokenURI}. | |
*/ | |
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
string memory baseURI = _baseURI(); | |
return bytes(baseURI).length > 0 | |
? string(abi.encodePacked(baseURI, tokenId.toString())) | |
: ''; | |
} | |
/** | |
* @dev Base URI for computing {tokenURI}. Empty by default, can be overriden | |
* in child contracts. | |
*/ | |
function _baseURI() internal view virtual returns (string memory) { | |
return ""; | |
} | |
/** | |
* @dev See {IERC721-approve}. | |
*/ | |
function approve(address to, uint256 tokenId) public virtual override { | |
address owner = ERC721.ownerOf(tokenId); | |
require(to != owner, "ERC721: approval to current owner"); | |
require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()), | |
"ERC721: approve caller is not owner nor approved for all" | |
); | |
_approve(to, tokenId); | |
} | |
/** | |
* @dev See {IERC721-getApproved}. | |
*/ | |
function getApproved(uint256 tokenId) public view virtual override returns (address) { | |
require(_exists(tokenId), "ERC721: approved query for nonexistent token"); | |
return _tokenApprovals[tokenId]; | |
} | |
/** | |
* @dev See {IERC721-setApprovalForAll}. | |
*/ | |
function setApprovalForAll(address operator, bool approved) public virtual override { | |
require(operator != _msgSender(), "ERC721: approve to caller"); | |
_operatorApprovals[_msgSender()][operator] = approved; | |
emit ApprovalForAll(_msgSender(), operator, approved); | |
} | |
/** | |
* @dev See {IERC721-isApprovedForAll}. | |
*/ | |
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) { | |
return _operatorApprovals[owner][operator]; | |
} | |
/** | |
* @dev See {IERC721-transferFrom}. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) public virtual override { | |
//solhint-disable-next-line max-line-length | |
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved"); | |
_transfer(from, to, tokenId); | |
} | |
/** | |
* @dev See {IERC721-safeTransferFrom}. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override { | |
safeTransferFrom(from, to, tokenId, ""); | |
} | |
/** | |
* @dev See {IERC721-safeTransferFrom}. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override { | |
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved"); | |
_safeTransfer(from, to, tokenId, _data); | |
} | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* `_data` is additional data, it has no specified format and it is sent in call to `to`. | |
* | |
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g. | |
* implement alternative mechanisms to perform token transfer, such as signature-based. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual { | |
_transfer(from, to, tokenId); | |
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer"); | |
} | |
/** | |
* @dev Returns whether `tokenId` exists. | |
* | |
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}. | |
* | |
* Tokens start existing when they are minted (`_mint`), | |
* and stop existing when they are burned (`_burn`). | |
*/ | |
function _exists(uint256 tokenId) internal view virtual returns (bool) { | |
return _owners[tokenId] != address(0); | |
} | |
/** | |
* @dev Returns whether `spender` is allowed to manage `tokenId`. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) { | |
require(_exists(tokenId), "ERC721: operator query for nonexistent token"); | |
address owner = ERC721.ownerOf(tokenId); | |
return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender)); | |
} | |
/** | |
* @dev Safely mints `tokenId` and transfers it to `to`. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must not exist. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _safeMint(address to, uint256 tokenId) internal virtual { | |
_safeMint(to, tokenId, ""); | |
} | |
/** | |
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is | |
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients. | |
*/ | |
function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual { | |
_mint(to, tokenId); | |
require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer"); | |
} | |
/** | |
* @dev Mints `tokenId` and transfers it to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible | |
* | |
* Requirements: | |
* | |
* - `tokenId` must not exist. | |
* - `to` cannot be the zero address. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _mint(address to, uint256 tokenId) internal virtual { | |
require(to != address(0), "ERC721: mint to the zero address"); | |
require(!_exists(tokenId), "ERC721: token already minted"); | |
_beforeTokenTransfer(address(0), to, tokenId); | |
_balances[to] += 1; | |
_owners[tokenId] = to; | |
emit Transfer(address(0), to, tokenId); | |
} | |
/** | |
* @dev Destroys `tokenId`. | |
* The approval is cleared when the token is burned. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _burn(uint256 tokenId) internal virtual { | |
address owner = ERC721.ownerOf(tokenId); | |
_beforeTokenTransfer(owner, address(0), tokenId); | |
// Clear approvals | |
_approve(address(0), tokenId); | |
_balances[owner] -= 1; | |
delete _owners[tokenId]; | |
emit Transfer(owner, address(0), tokenId); | |
} | |
/** | |
* @dev Transfers `tokenId` from `from` to `to`. | |
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender. | |
* | |
* Requirements: | |
* | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _transfer(address from, address to, uint256 tokenId) internal virtual { | |
require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); | |
require(to != address(0), "ERC721: transfer to the zero address"); | |
_beforeTokenTransfer(from, to, tokenId); | |
// Clear approvals from the previous owner | |
_approve(address(0), tokenId); | |
_balances[from] -= 1; | |
_balances[to] += 1; | |
_owners[tokenId] = to; | |
emit Transfer(from, to, tokenId); | |
} | |
/** | |
* @dev Approve `to` to operate on `tokenId` | |
* | |
* Emits a {Approval} event. | |
*/ | |
function _approve(address to, uint256 tokenId) internal virtual { | |
_tokenApprovals[tokenId] = to; | |
emit Approval(ERC721.ownerOf(tokenId), to, tokenId); | |
} | |
/** | |
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address. | |
* The call is not executed if the target address is not a contract. | |
* | |
* @param from address representing the previous owner of the given token ID | |
* @param to target address that will receive the tokens | |
* @param tokenId uint256 ID of the token to be transferred | |
* @param _data bytes optional data to send along with the call | |
* @return bool whether the call correctly returned the expected magic value | |
*/ | |
function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data) | |
private returns (bool) | |
{ | |
if (to.isContract()) { | |
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) { | |
return retval == IERC721Receiver(to).onERC721Received.selector; | |
} catch (bytes memory reason) { | |
if (reason.length == 0) { | |
revert("ERC721: transfer to non ERC721Receiver implementer"); | |
} else { | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
revert(add(32, reason), mload(reason)) | |
} | |
} | |
} | |
} else { | |
return true; | |
} | |
} | |
/** | |
* @dev Hook that is called before any token transfer. This includes minting | |
* and burning. | |
* | |
* Calling conditions: | |
* | |
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be | |
* transferred to `to`. | |
* - When `from` is zero, `tokenId` will be minted for `to`. | |
* - When `to` is zero, ``from``'s `tokenId` will be burned. | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* | |
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks]. | |
*/ | |
function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { } | |
} | |
contract CryptoCityMegaCityToken is ERC721 { | |
using Counters for Counters.Counter; | |
Counters.Counter private _tokenIds; | |
using SafeMath for uint256; | |
uint160 public itemCounts = 0; | |
uint160 private maxTokens = 100; | |
uint256 public priceOfNFT = 500000000000000000; | |
address payable public ownerContract; | |
///////////////////////////////////////////////////////////////////////////// | |
// Events | |
///////////////////////////////////////////////////////////////////////////// | |
constructor() ERC721("CryptoMegaCity" , "MegaCity"){ | |
ownerContract = payable(msg.sender); | |
} | |
struct Item { | |
uint256 id; | |
address creator; | |
string uri; | |
bool isCollection; | |
} | |
mapping (uint256 => Item) public Items; | |
function createItem(string memory uri) payable public returns (uint256){ | |
require(itemCounts < maxTokens, "Limit reached! you can't buy more MegaCitys"); | |
require(msg.value == priceOfNFT, "Sorry! you this is not the right amount to buy this nft"); | |
_tokenIds.increment(); | |
uint256 newItemId = _tokenIds.current(); | |
_safeMint(msg.sender, newItemId); | |
Items[newItemId] = Item(newItemId , msg.sender , uri, false); | |
itemCounts ++; | |
ownerContract.transfer(msg.value); | |
return newItemId; | |
} | |
function setRate(uint256 price) public { | |
require(_msgSender() == ownerContract , 'Only Owner'); | |
require(price != 0); | |
priceOfNFT = price; | |
} | |
function getTokenCreator(uint256 tokenId) external view returns (address) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
return Items[tokenId].creator; | |
} | |
function getItems() external view returns (address[] memory) { | |
address[] memory itms = new address[](itemCounts); | |
for (uint256 i = 0; i < itemCounts; i++) { | |
itms[i] = Items[i + 1].creator; | |
} | |
return itms; | |
} | |
function getItem(uint256 tokenId) external view returns (Item memory) { | |
return Items[tokenId]; | |
} | |
} |
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pragma solidity ^0.8.0; | |
// SPDX-License-Identifier: MIT | |
/** | |
* @dev Interface of the ERC165 standard, as defined in the | |
* https://eips.ethereum.org/EIPS/eip-165[EIP]. | |
* | |
* Implementers can declare support of contract interfaces, which can then be | |
* queried by others ({ERC165Checker}). | |
* | |
* For an implementation, see {ERC165}. | |
*/ | |
interface IERC165 { | |
/** | |
* @dev Returns true if this contract implements the interface defined by | |
* `interfaceId`. See the corresponding | |
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section] | |
* to learn more about how these ids are created. | |
* | |
* This function call must use less than 30 000 gas. | |
*/ | |
function supportsInterface(bytes4 interfaceId) external view returns (bool); | |
} | |
/** | |
* @dev Required interface of an ERC721 compliant contract. | |
*/ | |
interface IERC721 is IERC165 { | |
/** | |
* @dev Emitted when `tokenId` token is transferred from `from` to `to`. | |
*/ | |
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token. | |
*/ | |
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets. | |
*/ | |
event ApprovalForAll(address indexed owner, address indexed operator, bool approved); | |
/** | |
* @dev Returns the number of tokens in ``owner``'s account. | |
*/ | |
function balanceOf(address owner) external view returns (uint256 balance); | |
/** | |
* @dev Returns the owner of the `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function ownerOf(uint256 tokenId) external view returns (address owner); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Transfers `tokenId` token from `from` to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Gives permission to `to` to transfer `tokenId` token to another account. | |
* The approval is cleared when the token is transferred. | |
* | |
* Only a single account can be approved at a time, so approving the zero address clears previous approvals. | |
* | |
* Requirements: | |
* | |
* - The caller must own the token or be an approved operator. | |
* - `tokenId` must exist. | |
* | |
* Emits an {Approval} event. | |
*/ | |
function approve(address to, uint256 tokenId) external; | |
/** | |
* @dev Returns the account approved for `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function getApproved(uint256 tokenId) external view returns (address operator); | |
/** | |
* @dev Approve or remove `operator` as an operator for the caller. | |
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller. | |
* | |
* Requirements: | |
* | |
* - The `operator` cannot be the caller. | |
* | |
* Emits an {ApprovalForAll} event. | |
*/ | |
function setApprovalForAll(address operator, bool _approved) external; | |
/** | |
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`. | |
* | |
* See {setApprovalForAll} | |
*/ | |
function isApprovedForAll(address owner, address operator) external view returns (bool); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external; | |
} | |
/** | |
* @title ERC721 token receiver interface | |
* @dev Interface for any contract that wants to support safeTransfers | |
* from ERC721 asset contracts. | |
*/ | |
interface IERC721Receiver { | |
/** | |
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom} | |
* by `operator` from `from`, this function is called. | |
* | |
* It must return its Solidity selector to confirm the token transfer. | |
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted. | |
* | |
* The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`. | |
*/ | |
function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4); | |
} | |
/** | |
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension | |
* @dev See https://eips.ethereum.org/EIPS/eip-721 | |
*/ | |
interface IERC721Metadata is IERC721 { | |
/** | |
* @dev Returns the token collection name. | |
*/ | |
function name() external view returns (string memory); | |
/** | |
* @dev Returns the token collection symbol. | |
*/ | |
function symbol() external view returns (string memory); | |
/** | |
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token. | |
*/ | |
function tokenURI(uint256 tokenId) external view returns (string memory); | |
} | |
/** | |
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension | |
* @dev See https://eips.ethereum.org/EIPS/eip-721 | |
*/ | |
interface IERC721Enumerable is IERC721 { | |
/** | |
* @dev Returns the total amount of tokens stored by the contract. | |
*/ | |
function totalSupply() external view returns (uint256); | |
/** | |
* @dev Returns a token ID owned by `owner` at a given `index` of its token list. | |
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens. | |
*/ | |
function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId); | |
/** | |
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract. | |
* Use along with {totalSupply} to enumerate all tokens. | |
*/ | |
function tokenByIndex(uint256 index) external view returns (uint256); | |
} | |
abstract contract ERC165 is IERC165 { | |
/** | |
* @dev See {IERC165-supportsInterface}. | |
*/ | |
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) { | |
return interfaceId == type(IERC165).interfaceId; | |
} | |
} | |
/** | |
* @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; | |
// solhint-disable-next-line no-inline-assembly | |
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"); | |
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(bool success, bytes memory returndata) = target.delegatecall(data); | |
return _verifyCallResult(success, returndata, errorMessage); | |
} | |
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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 | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
let returndata_size := mload(returndata) | |
revert(add(32, returndata), returndata_size) | |
} | |
} else { | |
revert(errorMessage); | |
} | |
} | |
} | |
} | |
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) { | |
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) { | |
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) { | |
// 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) { | |
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) { | |
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) { | |
uint256 c = a + b; | |
require(c >= a, "SafeMath: addition overflow"); | |
return c; | |
} | |
/** | |
* @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) { | |
require(b <= a, "SafeMath: subtraction overflow"); | |
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) { | |
if (a == 0) return 0; | |
uint256 c = a * b; | |
require(c / a == b, "SafeMath: multiplication overflow"); | |
return c; | |
} | |
/** | |
* @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. 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) internal pure returns (uint256) { | |
require(b > 0, "SafeMath: division by zero"); | |
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) { | |
require(b > 0, "SafeMath: modulo by zero"); | |
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) { | |
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. | |
* | |
* CAUTION: This function is deprecated because it requires allocating memory for the error | |
* message unnecessarily. For custom revert reasons use {tryDiv}. | |
* | |
* 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) { | |
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) { | |
require(b > 0, errorMessage); | |
return a % b; | |
} | |
} | |
abstract contract Context { | |
function _msgSender() internal view virtual returns (address) { | |
return msg.sender; | |
} | |
function _msgData() internal view virtual returns (bytes calldata) { | |
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691 | |
return msg.data; | |
} | |
} | |
/** | |
* @dev String operations. | |
*/ | |
library Strings { | |
bytes16 private constant alphabet = "0123456789abcdef"; | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` decimal representation. | |
*/ | |
function toString(uint256 value) internal pure returns (string memory) { | |
// Inspired by OraclizeAPI's implementation - MIT licence | |
// 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); | |
} | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation. | |
*/ | |
function toHexString(uint256 value) internal pure returns (string memory) { | |
if (value == 0) { | |
return "0x00"; | |
} | |
uint256 temp = value; | |
uint256 length = 0; | |
while (temp != 0) { | |
length++; | |
temp >>= 8; | |
} | |
return toHexString(value, length); | |
} | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length. | |
*/ | |
function toHexString(uint256 value, uint256 length) internal pure returns (string memory) { | |
bytes memory buffer = new bytes(2 * length + 2); | |
buffer[0] = "0"; | |
buffer[1] = "x"; | |
for (uint256 i = 2 * length + 1; i > 1; --i) { | |
buffer[i] = alphabet[value & 0xf]; | |
value >>= 4; | |
} | |
require(value == 0, "Strings: hex length insufficient"); | |
return string(buffer); | |
} | |
} | |
/** | |
* @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;` | |
*/ | |
library Counters { | |
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 { | |
unchecked { | |
counter._value += 1; | |
} | |
} | |
function decrement(Counter storage counter) internal { | |
uint256 value = counter._value; | |
require(value > 0, "Counter: decrement overflow"); | |
unchecked { | |
counter._value = value - 1; | |
} | |
} | |
} | |
/** | |
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including | |
* the Metadata extension, but not including the Enumerable extension, which is available separately as | |
* {ERC721Enumerable}. | |
*/ | |
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata { | |
using Address for address; | |
using Strings for uint256; | |
// Token name | |
string private _name; | |
// Token symbol | |
string private _symbol; | |
// Mapping from token ID to owner address | |
mapping (uint256 => address) private _owners; | |
// Mapping owner address to token count | |
mapping (address => uint256) private _balances; | |
// Mapping from token ID to approved address | |
mapping (uint256 => address) private _tokenApprovals; | |
// Mapping from owner to operator approvals | |
mapping (address => mapping (address => bool)) private _operatorApprovals; | |
/** | |
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection. | |
*/ | |
constructor (string memory name_, string memory symbol_) { | |
_name = name_; | |
_symbol = symbol_; | |
} | |
/** | |
* @dev See {IERC165-supportsInterface}. | |
*/ | |
function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) { | |
return interfaceId == type(IERC721).interfaceId | |
|| interfaceId == type(IERC721Metadata).interfaceId | |
|| super.supportsInterface(interfaceId); | |
} | |
/** | |
* @dev See {IERC721-balanceOf}. | |
*/ | |
function balanceOf(address owner) public view virtual override returns (uint256) { | |
require(owner != address(0), "ERC721: balance query for the zero address"); | |
return _balances[owner]; | |
} | |
/** | |
* @dev See {IERC721-ownerOf}. | |
*/ | |
function ownerOf(uint256 tokenId) public view virtual override returns (address) { | |
address owner = _owners[tokenId]; | |
require(owner != address(0), "ERC721: owner query for nonexistent token"); | |
return owner; | |
} | |
/** | |
* @dev See {IERC721Metadata-name}. | |
*/ | |
function name() public view virtual override returns (string memory) { | |
return _name; | |
} | |
/** | |
* @dev See {IERC721Metadata-symbol}. | |
*/ | |
function symbol() public view virtual override returns (string memory) { | |
return _symbol; | |
} | |
/** | |
* @dev See {IERC721Metadata-tokenURI}. | |
*/ | |
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
string memory baseURI = _baseURI(); | |
return bytes(baseURI).length > 0 | |
? string(abi.encodePacked(baseURI, tokenId.toString())) | |
: ''; | |
} | |
/** | |
* @dev Base URI for computing {tokenURI}. Empty by default, can be overriden | |
* in child contracts. | |
*/ | |
function _baseURI() internal view virtual returns (string memory) { | |
return ""; | |
} | |
/** | |
* @dev See {IERC721-approve}. | |
*/ | |
function approve(address to, uint256 tokenId) public virtual override { | |
address owner = ERC721.ownerOf(tokenId); | |
require(to != owner, "ERC721: approval to current owner"); | |
require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()), | |
"ERC721: approve caller is not owner nor approved for all" | |
); | |
_approve(to, tokenId); | |
} | |
/** | |
* @dev See {IERC721-getApproved}. | |
*/ | |
function getApproved(uint256 tokenId) public view virtual override returns (address) { | |
require(_exists(tokenId), "ERC721: approved query for nonexistent token"); | |
return _tokenApprovals[tokenId]; | |
} | |
/** | |
* @dev See {IERC721-setApprovalForAll}. | |
*/ | |
function setApprovalForAll(address operator, bool approved) public virtual override { | |
require(operator != _msgSender(), "ERC721: approve to caller"); | |
_operatorApprovals[_msgSender()][operator] = approved; | |
emit ApprovalForAll(_msgSender(), operator, approved); | |
} | |
/** | |
* @dev See {IERC721-isApprovedForAll}. | |
*/ | |
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) { | |
return _operatorApprovals[owner][operator]; | |
} | |
/** | |
* @dev See {IERC721-transferFrom}. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) public virtual override { | |
//solhint-disable-next-line max-line-length | |
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved"); | |
_transfer(from, to, tokenId); | |
} | |
/** | |
* @dev See {IERC721-safeTransferFrom}. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override { | |
safeTransferFrom(from, to, tokenId, ""); | |
} | |
/** | |
* @dev See {IERC721-safeTransferFrom}. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override { | |
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved"); | |
_safeTransfer(from, to, tokenId, _data); | |
} | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* `_data` is additional data, it has no specified format and it is sent in call to `to`. | |
* | |
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g. | |
* implement alternative mechanisms to perform token transfer, such as signature-based. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual { | |
_transfer(from, to, tokenId); | |
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer"); | |
} | |
/** | |
* @dev Returns whether `tokenId` exists. | |
* | |
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}. | |
* | |
* Tokens start existing when they are minted (`_mint`), | |
* and stop existing when they are burned (`_burn`). | |
*/ | |
function _exists(uint256 tokenId) internal view virtual returns (bool) { | |
return _owners[tokenId] != address(0); | |
} | |
/** | |
* @dev Returns whether `spender` is allowed to manage `tokenId`. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) { | |
require(_exists(tokenId), "ERC721: operator query for nonexistent token"); | |
address owner = ERC721.ownerOf(tokenId); | |
return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender)); | |
} | |
/** | |
* @dev Safely mints `tokenId` and transfers it to `to`. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must not exist. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _safeMint(address to, uint256 tokenId) internal virtual { | |
_safeMint(to, tokenId, ""); | |
} | |
/** | |
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is | |
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients. | |
*/ | |
function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual { | |
_mint(to, tokenId); | |
require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer"); | |
} | |
/** | |
* @dev Mints `tokenId` and transfers it to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible | |
* | |
* Requirements: | |
* | |
* - `tokenId` must not exist. | |
* - `to` cannot be the zero address. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _mint(address to, uint256 tokenId) internal virtual { | |
require(to != address(0), "ERC721: mint to the zero address"); | |
require(!_exists(tokenId), "ERC721: token already minted"); | |
_beforeTokenTransfer(address(0), to, tokenId); | |
_balances[to] += 1; | |
_owners[tokenId] = to; | |
emit Transfer(address(0), to, tokenId); | |
} | |
/** | |
* @dev Destroys `tokenId`. | |
* The approval is cleared when the token is burned. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _burn(uint256 tokenId) internal virtual { | |
address owner = ERC721.ownerOf(tokenId); | |
_beforeTokenTransfer(owner, address(0), tokenId); | |
// Clear approvals | |
_approve(address(0), tokenId); | |
_balances[owner] -= 1; | |
delete _owners[tokenId]; | |
emit Transfer(owner, address(0), tokenId); | |
} | |
/** | |
* @dev Transfers `tokenId` from `from` to `to`. | |
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender. | |
* | |
* Requirements: | |
* | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _transfer(address from, address to, uint256 tokenId) internal virtual { | |
require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); | |
require(to != address(0), "ERC721: transfer to the zero address"); | |
_beforeTokenTransfer(from, to, tokenId); | |
// Clear approvals from the previous owner | |
_approve(address(0), tokenId); | |
_balances[from] -= 1; | |
_balances[to] += 1; | |
_owners[tokenId] = to; | |
emit Transfer(from, to, tokenId); | |
} | |
/** | |
* @dev Approve `to` to operate on `tokenId` | |
* | |
* Emits a {Approval} event. | |
*/ | |
function _approve(address to, uint256 tokenId) internal virtual { | |
_tokenApprovals[tokenId] = to; | |
emit Approval(ERC721.ownerOf(tokenId), to, tokenId); | |
} | |
/** | |
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address. | |
* The call is not executed if the target address is not a contract. | |
* | |
* @param from address representing the previous owner of the given token ID | |
* @param to target address that will receive the tokens | |
* @param tokenId uint256 ID of the token to be transferred | |
* @param _data bytes optional data to send along with the call | |
* @return bool whether the call correctly returned the expected magic value | |
*/ | |
function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data) | |
private returns (bool) | |
{ | |
if (to.isContract()) { | |
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) { | |
return retval == IERC721Receiver(to).onERC721Received.selector; | |
} catch (bytes memory reason) { | |
if (reason.length == 0) { | |
revert("ERC721: transfer to non ERC721Receiver implementer"); | |
} else { | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
revert(add(32, reason), mload(reason)) | |
} | |
} | |
} | |
} else { | |
return true; | |
} | |
} | |
/** | |
* @dev Hook that is called before any token transfer. This includes minting | |
* and burning. | |
* | |
* Calling conditions: | |
* | |
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be | |
* transferred to `to`. | |
* - When `from` is zero, `tokenId` will be minted for `to`. | |
* - When `to` is zero, ``from``'s `tokenId` will be burned. | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* | |
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks]. | |
*/ | |
function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { } | |
} | |
contract CryptoCityToken is ERC721 { | |
using Counters for Counters.Counter; | |
Counters.Counter private _tokenIds; | |
using SafeMath for uint256; | |
address payable public ownerContract; | |
///////////////////////////////////////////////////////////////////////////// | |
// Events | |
///////////////////////////////////////////////////////////////////////////// | |
constructor() ERC721("CryptoCityCollection" , "CCC"){ | |
ownerContract = payable(msg.sender); | |
} | |
struct Item { | |
uint256 id; | |
address creator; | |
string uri; | |
bool isCollection; | |
} | |
mapping (uint256 => Item) public Items; | |
function createItemOwner(string memory uri) public returns (uint256){ | |
require(_msgSender() == ownerContract , 'Only Owner'); | |
_tokenIds.increment(); | |
uint256 newItemId = _tokenIds.current(); | |
_safeMint(msg.sender, newItemId); | |
Items[newItemId] = Item(newItemId , msg.sender , uri, true); | |
return newItemId; | |
} | |
function createItems(string[] memory uris) public returns (uint256[] memory){ | |
uint256[] memory itms = new uint256[](uris.length); | |
for (uint i = 0; i < uris.length; i++) { | |
_tokenIds.increment(); | |
uint256 newItemId = _tokenIds.current(); | |
_safeMint(msg.sender, newItemId); | |
Items[newItemId] = Item(newItemId , msg.sender , uris[i], true); | |
itms[i] = newItemId; | |
} | |
return itms; | |
} | |
function tokenURI(uint256 tokenId) public view override returns (string memory) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
return Items[tokenId].uri; | |
} | |
function getTokenCreator(uint256 tokenId) external view returns (address) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
return Items[tokenId].creator; | |
} | |
function getItem(uint256 tokenId) external view returns (Item memory) { | |
return Items[tokenId]; | |
} | |
} |
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pragma solidity 0.6.12; | |
pragma experimental ABIEncoderV2; | |
interface CryptoCityToken { | |
struct Item { | |
uint256 id; | |
address creator; | |
string uri; | |
bool isCollection; | |
} | |
function getItems() external view returns (address [] memory); | |
function getItem(uint256 tokenId) external view returns (Item memory); | |
function getTokenCreator(uint256 tokenId) external view returns (address); | |
} | |
// SPDX-License-Identifier: MIT | |
interface IERC165 { | |
/** | |
* @dev Returns true if this contract implements the interface defined by | |
* `interfaceId`. See the corresponding | |
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section] | |
* to learn more about how these ids are created. | |
* | |
* This function call must use less than 30 000 gas. | |
*/ | |
function supportsInterface(bytes4 interfaceId) external view returns (bool); | |
} | |
/** | |
* @dev Required interface of an ERC721 compliant contract. | |
*/ | |
interface IERC721 is IERC165 { | |
struct Item { | |
uint256 id; | |
address creator; | |
string uri; | |
bool isCollection; | |
} | |
/** | |
* @dev Emitted when `tokenId` token is transferred from `from` to `to`. | |
*/ | |
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token. | |
*/ | |
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets. | |
*/ | |
event ApprovalForAll(address indexed owner, address indexed operator, bool approved); | |
/** | |
* @dev Returns the number of tokens in ``owner``'s account. | |
*/ | |
function balanceOf(address owner) external view returns (uint256 balance); | |
function items(uint256 _tokenId) external view returns (Item memory); | |
/** | |
* @dev Returns the owner of the `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function ownerOf(uint256 tokenId) external view returns (address owner); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Transfers `tokenId` token from `from` to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Gives permission to `to` to transfer `tokenId` token to another account. | |
* The approval is cleared when the token is transferred. | |
* | |
* Only a single account can be approved at a time, so approving the zero address clears previous approvals. | |
* | |
* Requirements: | |
* | |
* - The caller must own the token or be an approved operator. | |
* - `tokenId` must exist. | |
* | |
* Emits an {Approval} event. | |
*/ | |
function approve(address to, uint256 tokenId) external; | |
/** | |
* @dev Returns the account approved for `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function getApproved(uint256 tokenId) external view returns (address operator); | |
/** | |
* @dev Approve or remove `operator` as an operator for the caller. | |
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller. | |
* | |
* Requirements: | |
* | |
* - The `operator` cannot be the caller. | |
* | |
* Emits an {ApprovalForAll} event. | |
*/ | |
function setApprovalForAll(address operator, bool _approved) external; | |
/** | |
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`. | |
* | |
* See {setApprovalForAll} | |
*/ | |
function isApprovedForAll(address owner, address operator) external view returns (bool); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external; | |
} | |
/** | |
* @dev Wrappers over Solidity's arithmetic operations with added overflow | |
* checks. | |
* | |
* Arithmetic operations in Solidity wrap on overflow. This can easily result | |
* in bugs, because programmers usually assume that an overflow raises an | |
* error, which is the standard behavior in high level programming languages. | |
* `SafeMath` restores this intuition by reverting the transaction when an | |
* operation overflows. | |
* | |
* Using this library instead of the unchecked operations eliminates an entire | |
* class of bugs, so it's recommended to use it always. | |
*/ | |
library SafeMathUpgradeable { | |
/** | |
* @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) { | |
uint256 c = a + b; | |
require(c >= a, "SafeMath: addition overflow"); | |
return c; | |
} | |
/** | |
* @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 sub(a, b, "SafeMath: subtraction overflow"); | |
} | |
/** | |
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on | |
* overflow (when the result is negative). | |
* | |
* Counterpart to Solidity's `-` operator. | |
* | |
* Requirements: | |
* | |
* - Subtraction cannot overflow. | |
*/ | |
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) { | |
require(b <= a, errorMessage); | |
uint256 c = a - b; | |
return c; | |
} | |
/** | |
* @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) { | |
// 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 0; | |
} | |
uint256 c = a * b; | |
require(c / a == b, "SafeMath: multiplication overflow"); | |
return c; | |
} | |
/** | |
* @dev Returns the integer division of two unsigned integers. Reverts 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) internal pure returns (uint256) { | |
return div(a, b, "SafeMath: division by zero"); | |
} | |
/** | |
* @dev Returns the integer division of two unsigned integers. Reverts 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) { | |
require(b > 0, errorMessage); | |
uint256 c = a / b; | |
// assert(a == b * c + a % b); // There is no case in which this doesn't hold | |
return c; | |
} | |
/** | |
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo), | |
* Reverts 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 mod(a, b, "SafeMath: modulo by zero"); | |
} | |
/** | |
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo), | |
* Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) { | |
require(b != 0, errorMessage); | |
return a % b; | |
} | |
} | |
/** | |
* @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 Initializable { | |
/** | |
* @dev Indicates that the contract has been initialized. | |
*/ | |
bool private _initialized; | |
/** | |
* @dev Indicates that the contract is in the process of being initialized. | |
*/ | |
bool private _initializing; | |
/** | |
* @dev Modifier to protect an initializer function from being invoked twice. | |
*/ | |
modifier initializer() { | |
require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized"); | |
bool isTopLevelCall = !_initializing; | |
if (isTopLevelCall) { | |
_initializing = true; | |
_initialized = true; | |
} | |
_; | |
if (isTopLevelCall) { | |
_initializing = false; | |
} | |
} | |
/// @dev Returns true if and only if the function is running in the constructor | |
function _isConstructor() private view returns (bool) { | |
// extcodesize checks the size of the code stored in an address, and | |
// address returns the current address. Since the code is still not | |
// deployed when running a constructor, any checks on its code size will | |
// yield zero, making it an effective way to detect if a contract is | |
// under construction or not. | |
address self = address(this); | |
uint256 cs; | |
// solhint-disable-next-line no-inline-assembly | |
assembly { cs := extcodesize(self) } | |
return cs == 0; | |
} | |
} | |
abstract contract ContextUpgradeable is Initializable { | |
function __Context_init() internal initializer { | |
__Context_init_unchained(); | |
} | |
function __Context_init_unchained() internal initializer { | |
} | |
function _msgSender() internal view virtual returns (address payable) { | |
return msg.sender; | |
} | |
function _msgData() internal view virtual returns (bytes memory) { | |
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691 | |
return msg.data; | |
} | |
uint256[50] private __gap; | |
} | |
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable { | |
address private _owner; | |
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); | |
/** | |
* @dev Initializes the contract setting the deployer as the initial owner. | |
*/ | |
function __Ownable_init() internal initializer { | |
__Context_init_unchained(); | |
__Ownable_init_unchained(); | |
} | |
function __Ownable_init_unchained() internal initializer { | |
address msgSender = _msgSender(); | |
_owner = msgSender; | |
emit OwnershipTransferred(address(0), msgSender); | |
} | |
/** | |
* @dev Returns the address of the current owner. | |
*/ | |
function owner() public view 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 { | |
emit OwnershipTransferred(_owner, address(0)); | |
_owner = 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"); | |
emit OwnershipTransferred(_owner, newOwner); | |
_owner = newOwner; | |
} | |
uint256[49] private __gap; | |
} | |
library AddressUpgradeable { | |
/** | |
* @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; | |
// solhint-disable-next-line no-inline-assembly | |
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"); | |
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(bool success, bytes memory returndata) = target.staticcall(data); | |
return _verifyCallResult(success, returndata, errorMessage); | |
} | |
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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 | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
let returndata_size := mload(returndata) | |
revert(add(32, returndata), returndata_size) | |
} | |
} else { | |
revert(errorMessage); | |
} | |
} | |
} | |
} | |
contract EscrowUpgradeable is Initializable, OwnableUpgradeable { | |
function initialize() public virtual initializer { | |
__Escrow_init(); | |
} | |
function __Escrow_init() internal initializer { | |
__Context_init_unchained(); | |
__Ownable_init_unchained(); | |
__Escrow_init_unchained(); | |
} | |
function __Escrow_init_unchained() internal initializer { | |
} | |
using SafeMathUpgradeable for uint256; | |
using AddressUpgradeable for address payable; | |
event Deposited(address indexed payee, uint256 weiAmount); | |
event Withdrawn(address indexed payee, uint256 weiAmount); | |
mapping(address => uint256) private _deposits; | |
function depositsOf(address payee) public view returns (uint256) { | |
return _deposits[payee]; | |
} | |
/** | |
* @dev Stores the sent amount as credit to be withdrawn. | |
* @param payee The destination address of the funds. | |
*/ | |
function deposit(address payee) public virtual payable onlyOwner { | |
uint256 amount = msg.value; | |
_deposits[payee] = _deposits[payee].add(amount); | |
emit Deposited(payee, amount); | |
} | |
/** | |
* @dev Withdraw accumulated balance for a payee, forwarding all gas to the | |
* recipient. | |
* | |
* WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities. | |
* Make sure you trust the recipient, or are either following the | |
* checks-effects-interactions pattern or using {ReentrancyGuard}. | |
* | |
* @param payee The address whose funds will be withdrawn and transferred to. | |
*/ | |
function withdraw(address payable payee) public virtual onlyOwner { | |
uint256 payment = _deposits[payee]; | |
_deposits[payee] = 0; | |
payee.sendValue(payment); | |
emit Withdrawn(payee, payment); | |
} | |
uint256[49] private __gap; | |
} | |
abstract contract PullPaymentUpgradeable is Initializable { | |
EscrowUpgradeable private _escrow; | |
function __PullPayment_init() internal initializer { | |
__PullPayment_init_unchained(); | |
} | |
function __PullPayment_init_unchained() internal initializer { | |
_escrow = new EscrowUpgradeable(); | |
_escrow.initialize(); | |
} | |
/** | |
* @dev Withdraw accumulated payments, forwarding all gas to the recipient. | |
* | |
* Note that _any_ account can call this function, not just the `payee`. | |
* This means that contracts unaware of the `PullPayment` protocol can still | |
* receive funds this way, by having a separate account call | |
* {withdrawPayments}. | |
* | |
* WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities. | |
* Make sure you trust the recipient, or are either following the | |
* checks-effects-interactions pattern or using {ReentrancyGuard}. | |
* | |
* @param payee Whose payments will be withdrawn. | |
*/ | |
function withdrawPayments(address payable payee) public virtual { | |
_escrow.withdraw(payee); | |
} | |
/** | |
* @dev Returns the payments owed to an address. | |
* @param dest The creditor's address. | |
*/ | |
function payments(address dest) public view returns (uint256) { | |
return _escrow.depositsOf(dest); | |
} | |
/** | |
* @dev Called by the payer to store the sent amount as credit to be pulled. | |
* Funds sent in this way are stored in an intermediate {Escrow} contract, so | |
* there is no danger of them being spent before withdrawal. | |
* | |
* @param dest The destination address of the funds. | |
* @param amount The amount to transfer. | |
*/ | |
function _asyncTransfer(address dest, uint256 amount) internal virtual { | |
_escrow.deposit{ value: amount }(dest); | |
} | |
uint256[49] private __gap; | |
} | |
interface ISendValueProxy { | |
function sendValue(address payable _to) external payable; | |
} | |
/** | |
* @dev Contract that attempts to send value to an address. | |
*/ | |
contract SendValueProxy is ISendValueProxy { | |
/** | |
* @dev Send some wei to the address. | |
* @param _to address to send some value to. | |
*/ | |
function sendValue(address payable _to) external override payable { | |
// Note that `<address>.transfer` limits gas sent to receiver. It may | |
// not support complex contract operations in the future. | |
_to.transfer(msg.value); | |
} | |
} | |
/** | |
* @dev Contract with a ISendValueProxy that will catch reverts when attempting to transfer funds. | |
*/ | |
contract MaybeSendValue { | |
SendValueProxy proxy; | |
// constructor() internal { | |
// proxy = new SendValueProxy(); | |
// } | |
constructor() public { | |
proxy = new SendValueProxy(); | |
} | |
/** | |
* @dev Maybe send some wei to the address via a proxy. Returns true on success and false if transfer fails. | |
* @param _to address to send some value to. | |
* @param _value uint256 amount to send. | |
*/ | |
function maybeSendValue(address payable _to, uint256 _value) | |
internal | |
returns (bool) | |
{ | |
// Call sendValue on the proxy contract and forward the mesg.value. | |
/* solium-disable-next-line */ | |
(bool success,) = address(proxy).call{value : _value}( | |
abi.encodeWithSignature("sendValue(address)", _to) | |
); | |
return success; | |
} | |
} | |
/** | |
* @dev Contract to make payments. If a direct transfer fails, it will store the payment in escrow until the address decides to pull the payment. | |
*/ | |
contract SendValueOrEscrow is MaybeSendValue, PullPaymentUpgradeable { | |
///////////////////////////////////////////////////////////////////////// | |
// Events | |
///////////////////////////////////////////////////////////////////////// | |
event SendValue(address indexed _payee, uint256 amount); | |
///////////////////////////////////////////////////////////////////////// | |
// sendValueOrEscrow | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Send some value to an address. | |
* @param _to address to send some value to. | |
* @param _value uint256 amount to send. | |
*/ | |
function sendValueOrEscrow(address payable _to, uint256 _value) internal { | |
// attempt to make the transfer | |
_to.transfer(_value); | |
// if it fails, transfer it into escrow for them to redeem at their will. | |
// if (!successfulTransfer) { | |
// _asyncTransfer(_to, _value); | |
// } | |
emit SendValue(_to, _value); | |
} | |
function sendViaTransfer(address payable _to, uint256 _value) internal { | |
// This function is no longer recommended for sending Ether. | |
_to.transfer(_value); | |
} | |
function sendViaSend(address payable _to, uint256 _value) internal { | |
// Send returns a boolean value indicating success or failure. | |
// This function is not recommended for sending Ether. | |
bool sent = _to.send(_value); | |
require(sent, "Failed to send Ether"); | |
} | |
} | |
/** | |
* @title Payments contract for SuperRare Marketplaces. | |
*/ | |
contract Payments is SendValueOrEscrow { | |
using SafeMathUpgradeable for uint256; | |
using SafeMathUpgradeable for uint8; | |
///////////////////////////////////////////////////////////////////////// | |
// refund | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to refund an address. Typically for canceled bids or offers. | |
* Requirements: | |
* | |
* - _payee cannot be the zero address | |
* | |
* @param _marketplacePercentage uint8 percentage of the fee for the marketplace. | |
* @param _amount uint256 value to be split. | |
* @param _payee address seller of the token. | |
*/ | |
function refund( | |
uint8 _marketplacePercentage, | |
address payable _payee, | |
uint256 _amount | |
) internal { | |
require( | |
_payee != address(0), | |
"refund::no payees can be the zero address" | |
); | |
if (_amount > 0) { | |
SendValueOrEscrow.sendValueOrEscrow( | |
_payee, | |
_amount.add( | |
calcPercentagePayment(_amount, _marketplacePercentage) | |
) | |
); | |
} | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// payout | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to pay the seller, creator, and maintainer. | |
* Requirements: | |
* | |
* - _marketplacePercentage + _royaltyPercentage + _primarySalePercentage <= 100 | |
* - no payees can be the zero address | |
* | |
* @param _amount uint256 value to be split. | |
* @param _isPrimarySale bool of whether this is a primary sale. | |
* @param _marketplacePercentage uint8 percentage of the fee for the marketplace. | |
* @param _royaltyPercentage uint8 percentage of the fee for the royalty. | |
* @param _primarySalePercentage uint8 percentage primary sale fee for the marketplace. | |
* @param _payee address seller of the token. | |
* @param _marketplacePayee address seller of the token. | |
* @param _royaltyPayee address seller of the token. | |
* @param _primarySalePayee address seller of the token. | |
*/ | |
function payout( | |
uint256 _amount, | |
bool _isPrimarySale, | |
uint8 _marketplacePercentage, | |
uint8 _royaltyPercentage, | |
uint8 _primarySalePercentage, | |
address payable _payee, | |
address payable _marketplacePayee, | |
address payable _royaltyPayee, | |
address payable _primarySalePayee | |
) internal { | |
require( | |
_marketplacePercentage <= 100, | |
"payout::marketplace percentage cannot be above 100" | |
); | |
require( | |
_royaltyPercentage.add(_primarySalePercentage) <= 100, | |
"payout::percentages cannot go beyond 100" | |
); | |
require( | |
_payee != address(0) && | |
_primarySalePayee != address(0) && | |
_marketplacePayee != address(0) && | |
_royaltyPayee != address(0), | |
"payout::no payees can be the zero address" | |
); | |
// Note:: Solidity is kind of terrible in that there is a limit to local | |
// variables that can be put into the stack. The real pain is that | |
// one can put structs, arrays, or mappings into memory but not basic | |
// data types. Hence our payments array that stores these values. | |
uint256[4] memory payments; | |
// uint256 marketplacePayment | |
payments[0] = calcPercentagePayment(_amount, _marketplacePercentage); | |
// uint256 royaltyPayment | |
payments[1] = calcRoyaltyPayment( | |
_isPrimarySale, | |
_amount, | |
_royaltyPercentage | |
); | |
// uint256 primarySalePayment | |
payments[2] = calcPrimarySalePayment( | |
_isPrimarySale, | |
_amount, | |
_primarySalePercentage | |
); | |
// uint256 payeePayment | |
payments[3] = _amount.sub(payments[1]).sub(payments[2]); | |
// marketplacePayment | |
if (payments[0] > 0) { | |
SendValueOrEscrow.sendValueOrEscrow(_marketplacePayee, payments[0]); | |
// SendValueOrEscrow.sendViaCall(_marketplacePayee, payments[0]-1); | |
} | |
// royaltyPayment | |
if (payments[1] > 0) { | |
SendValueOrEscrow.sendValueOrEscrow(_royaltyPayee, payments[1]); | |
// SendValueOrEscrow.sendViaCall(_royaltyPayee, payments[1]-1); | |
} | |
// primarySalePayment | |
if (payments[2] > 0) { | |
SendValueOrEscrow.sendValueOrEscrow(_primarySalePayee, payments[2]); | |
// SendValueOrEscrow.sendViaCall(_primarySalePayee, payments[2]-1); | |
} | |
// payeePayment | |
if (payments[3] > 0) { | |
SendValueOrEscrow.sendValueOrEscrow(_payee, payments[3]); | |
// SendValueOrEscrow.sendViaCall(_payee, payments[3]-1); | |
} | |
} | |
function simplePayout( | |
uint256 _amount, | |
address payable _payee | |
) internal { | |
require( | |
_payee != address(0), | |
"payout::no payees can be the zero address" | |
); | |
SendValueOrEscrow.sendValueOrEscrow(_payee, _amount); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// calcRoyaltyPayment | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Private function to calculate Royalty amount. | |
* If primary sale: 0 | |
* If no royalty percentage: 0 | |
* otherwise: royalty in wei | |
* @param _isPrimarySale bool of whether this is a primary sale | |
* @param _amount uint256 value to be split | |
* @param _percentage uint8 royalty percentage | |
* @return uint256 wei value owed for royalty | |
*/ | |
function calcRoyaltyPayment( | |
bool _isPrimarySale, | |
uint256 _amount, | |
uint8 _percentage | |
) private pure returns (uint256) { | |
if (_isPrimarySale) { | |
return 0; | |
} | |
return calcPercentagePayment(_amount, _percentage); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// calcPrimarySalePayment | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Private function to calculate PrimarySale amount. | |
* If not primary sale: 0 | |
* otherwise: primary sale in wei+ | |
* @param _isPrimarySale bool of whether this is a primary sale | |
* @param _amount uint256 value to be split | |
* @param _percentage uint8 royalty percentage | |
* @return uint256 wei value owed for primary sale | |
*/ | |
function calcPrimarySalePayment( | |
bool _isPrimarySale, | |
uint256 _amount, | |
uint8 _percentage | |
) private pure returns (uint256) { | |
if (_isPrimarySale) { | |
return calcPercentagePayment(_amount, _percentage); | |
} | |
return 0; | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// calcPercentagePayment | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to calculate percentage value. | |
* @param _amount uint256 wei value | |
* @param _percentage uint8 percentage | |
* @return uint256 wei value based on percentage. | |
*/ | |
function calcPercentagePayment(uint256 _amount, uint8 _percentage) | |
internal | |
pure | |
returns (uint256) | |
{ | |
return _amount.mul(_percentage).div(100); | |
} | |
} | |
contract MarketPlace is OwnableUpgradeable, Payments { | |
using SafeMathUpgradeable for uint256; | |
// Market fee on sales | |
uint8 public marketplacePercentage = 5; | |
uint8 public devTeamPercentage = 25; | |
uint8 public marketingTeamPercentage = 25; | |
// City Addresses | |
address public Village; | |
address public County; | |
address public Town; | |
address public Metropolis; | |
address public MegaCity; | |
// Team Wallet | |
address public devTeam; | |
address public marketingTeam; | |
///////////////////////////////////////////////////////////////////////// | |
// Structs | |
///////////////////////////////////////////////////////////////////////// | |
// The active bid for a given token, contains the bidder, the marketplace fee at the time of the bid, and the amount of wei placed on the token | |
struct ActiveBid { | |
address payable bidder; | |
uint8 marketplaceFee; | |
uint256 amount; | |
} | |
// The sale price for a given token containing the seller and the amount of wei to be sold for | |
struct SalePrice { | |
address payable seller; | |
uint256 amount; | |
} | |
// Mapping from ERC721 contract to mapping of tokenId to sale price. | |
mapping(address => mapping(uint256 => SalePrice)) private tokenPrices; | |
// Mapping of ERC721 contract to mapping of token ID to the current bid amount. | |
mapping(address => mapping(uint256 => ActiveBid)) private tokenCurrentBids; | |
// A minimum increase in bid amount when out bidding someone. | |
uint8 public minimumBidIncreasePercentage; // 10 = 10% | |
///////////////////////////////////////////////////////////////////////////// | |
// Events | |
///////////////////////////////////////////////////////////////////////////// | |
event ChangedMarketPlacePercentage( | |
uint8 marketplacePercentage | |
); | |
event ChangedDevTeamPercentage( | |
uint8 devTeamPercentage | |
); | |
event ChangedMarkingTeamPercentage( | |
uint8 marketingTeamPercentage | |
); | |
event Sold( | |
address indexed _originContract, | |
address indexed _buyer, | |
address indexed _seller, | |
uint256 _amount, | |
uint256 _tokenId | |
); | |
event SetSalePrice( | |
address indexed _originContract, | |
uint256 _amount, | |
uint256 _tokenId | |
); | |
event Bid( | |
address indexed _originContract, | |
address indexed _bidder, | |
uint256 _amount, | |
uint256 _tokenId | |
); | |
event AcceptBid( | |
address indexed _originContract, | |
address indexed _bidder, | |
address indexed _seller, | |
uint256 _amount, | |
uint256 _tokenId | |
); | |
event CancelBid( | |
address indexed _originContract, | |
address indexed _bidder, | |
uint256 _amount, | |
uint256 _tokenId | |
); | |
///////////////////////////////////////////////////////////////////////// | |
// Constructor | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Initializes the contract setting the market settings and creator royalty interfaces. | |
*/ | |
constructor( | |
address _village, | |
address _county, | |
address _town, | |
address _metropolis, | |
address _megaCity, | |
address _devTeam, | |
address _marketingTeam | |
) | |
public | |
{ | |
minimumBidIncreasePercentage = 5; | |
Village = _village; | |
County = _county; | |
Town = _town; | |
Metropolis = _metropolis; | |
MegaCity = _megaCity; | |
devTeam = _devTeam; | |
marketingTeam = _marketingTeam; | |
__Ownable_init(); | |
} | |
/** | |
* @dev Sets the share cut for the owner of the contract that's | |
* charged to the seller on a successful sale | |
* @param _marketplacePercentage - Share amount, from 0 to 99 | |
*/ | |
function setMarketPlacePercentage(uint8 _marketplacePercentage) external onlyOwner { | |
require( | |
_marketplacePercentage < 100, | |
"The owner cut should be less then 100%" | |
); | |
marketplacePercentage = _marketplacePercentage; | |
emit ChangedMarketPlacePercentage(marketplacePercentage); | |
} | |
function setDevTeamPercentage(uint8 _devTeamPercentage) external onlyOwner { | |
require( | |
_devTeamPercentage < 100, | |
"The dev cut should be less then 100%" | |
); | |
devTeamPercentage = _devTeamPercentage; | |
emit ChangedDevTeamPercentage(devTeamPercentage); | |
} | |
function setMarketingTeamPercentage(uint8 _marketingTeamPercentage) external onlyOwner { | |
require( | |
_marketingTeamPercentage < 100, | |
"The marketing cut should be less then 100%" | |
); | |
marketingTeamPercentage = _marketingTeamPercentage; | |
emit ChangedMarketPlacePercentage(marketingTeamPercentage); | |
} | |
/** | |
* @dev Admin function to set the minimum bid increase percentage. | |
* Rules: | |
* - only owner | |
* @param _percentage uint8 to set as the new percentage. | |
*/ | |
function setMinimumBidIncreasePercentage(uint8 _percentage) | |
public | |
onlyOwner | |
{ | |
minimumBidIncreasePercentage = _percentage; | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// Modifiers (as functions) | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Checks that the token owner is approved for the ERC721Market | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
*/ | |
function ownerMustHaveMarketplaceApproved( | |
address _originContract, | |
uint256 _tokenId | |
) internal view { | |
IERC721 erc721 = IERC721(_originContract); | |
address owner = erc721.ownerOf(_tokenId); | |
require( | |
erc721.isApprovedForAll(owner, address(this)), | |
"owner must have approved contract" | |
); | |
} | |
/** | |
* @dev Checks that the token is owned by the sender | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
*/ | |
function senderMustBeTokenOwner(address _originContract, uint256 _tokenId) | |
internal | |
view | |
{ | |
IERC721 erc721 = IERC721(_originContract); | |
require( | |
erc721.ownerOf(_tokenId) == msg.sender, | |
"sender must be the token owner" | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// setSalePrice | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Set the token for sale. The owner of the token must be the sender and have the marketplace approved. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
* @param _amount uint256 wei value that the item is for sale | |
*/ | |
function setSalePrice( | |
address _originContract, | |
uint256 _tokenId, | |
uint256 _amount | |
) external { | |
// The owner of the token must have the marketplace approved | |
ownerMustHaveMarketplaceApproved(_originContract, _tokenId); | |
// The sender must be the token owner | |
senderMustBeTokenOwner(_originContract, _tokenId); | |
if (_amount == 0) { | |
// Set not for sale and exit | |
_resetTokenPrice(_originContract, _tokenId); | |
emit SetSalePrice(_originContract, _amount, _tokenId); | |
return; | |
} | |
tokenPrices[_originContract][_tokenId] = SalePrice(msg.sender, _amount); | |
emit SetSalePrice(_originContract, _amount, _tokenId); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// safeBuy | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Purchase the token with the expected amount. The current token owner must have the marketplace approved. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
* @param _amount uint256 wei amount expecting to purchase the token for. | |
*/ | |
function safeBuy( | |
address _originContract, | |
uint256 _tokenId, | |
uint256 _amount | |
) external payable { | |
// Make sure the tokenPrice is the expected amount | |
require( | |
tokenPrices[_originContract][_tokenId].amount == _amount, | |
"safeBuy::Purchase amount must equal expected amount" | |
); | |
buy(_originContract, _tokenId); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// buy | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Purchases the token if it is for sale. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token. | |
*/ | |
function buy(address _originContract, uint256 _tokenId) public payable { | |
// The owner of the token must have the marketplace approved | |
ownerMustHaveMarketplaceApproved(_originContract, _tokenId); | |
// Check that the person who set the price still owns the token. | |
require( | |
_priceSetterStillOwnsTheToken(_originContract, _tokenId), | |
"buy::Current token owner must be the person to have the latest price." | |
); | |
SalePrice memory sp = tokenPrices[_originContract][_tokenId]; | |
// Check that token is for sale. | |
require(sp.amount > 0, "buy::Tokens priced at 0 are not for sale."); | |
// Check that enough ether was sent. | |
require( | |
tokenPriceFeeIncluded(_originContract, _tokenId) == msg.value, | |
"buy::Must purchase the token for the correct price(buy)" | |
); | |
// Get token contract details. | |
IERC721 erc721 = IERC721(_originContract); | |
address tokenOwner = erc721.ownerOf(_tokenId); | |
// Wipe the token price. | |
_resetTokenPrice(_originContract, _tokenId); | |
// Transfer token. | |
erc721.safeTransferFrom(tokenOwner, msg.sender, _tokenId); | |
// if the buyer had an existing bid, return it | |
if (_addressHasBidOnToken(msg.sender, _originContract, _tokenId)) { | |
_refundBid(_originContract, _tokenId); | |
} | |
// Payout all parties. | |
_distributeFees(tokenOwner ,sp.amount); | |
emit Sold(_originContract, msg.sender, tokenOwner, sp.amount, _tokenId); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// tokenPrice | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Gets the sale price of the token | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
* @return uint256 sale price of the token | |
*/ | |
function tokenPrice(address _originContract, uint256 _tokenId) | |
external | |
view | |
returns (uint256) | |
{ | |
// The owner of the token must have the marketplace approved | |
ownerMustHaveMarketplaceApproved(_originContract, _tokenId); // TODO: Make sure to write test to verify that this returns 0 when it fails | |
if (_priceSetterStillOwnsTheToken(_originContract, _tokenId)) { | |
return tokenPrices[_originContract][_tokenId].amount; | |
} | |
return 0; | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// tokenPriceFeeIncluded | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Gets the sale price of the token including the marketplace fee. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
* @return uint256 sale price of the token including the fee. | |
*/ | |
function tokenPriceFeeIncluded(address _originContract, uint256 _tokenId) | |
public | |
view | |
returns (uint256) | |
{ | |
// The owner of the token must have the marketplace approved | |
ownerMustHaveMarketplaceApproved(_originContract, _tokenId); // TODO: Make sure to write test to verify that this returns 0 when it fails | |
if (_priceSetterStillOwnsTheToken(_originContract, _tokenId)) { | |
return | |
tokenPrices[_originContract][_tokenId].amount.add(0); | |
} | |
return 0; | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// bid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Bids on the token, replacing the bid if the bid is higher than the current bid. You cannot bid on a token you already own. | |
* @param _newBidAmount uint256 value in wei to bid. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
*/ | |
function bid( | |
uint256 _newBidAmount, | |
address _originContract, | |
uint256 _tokenId | |
) external payable { | |
// Check that bid is greater than 0. | |
require(_newBidAmount > 0, "bid::Cannot bid 0 Wei."); | |
// Check that bid is higher than previous bid | |
uint256 currentBidAmount = | |
tokenCurrentBids[_originContract][_tokenId].amount; | |
require( | |
_newBidAmount > currentBidAmount && | |
_newBidAmount >= | |
currentBidAmount.add( | |
currentBidAmount.mul(minimumBidIncreasePercentage).div(100) | |
), | |
"bid::Must place higher bid than existing bid + minimum percentage." | |
); | |
// Check that enough ether was sent. | |
uint256 requiredCost = | |
_newBidAmount.add( | |
0 | |
); | |
require( | |
requiredCost == msg.value, | |
"bid::Must purchase the token for the correct price." | |
); | |
// Check that bidder is not owner. | |
IERC721 erc721 = IERC721(_originContract); | |
address tokenOwner = erc721.ownerOf(_tokenId); | |
require(tokenOwner != msg.sender, "bid::Bidder cannot be owner."); | |
// Refund previous bidder. | |
_refundBid(_originContract, _tokenId); | |
// Set the new bid. | |
_setBid(_newBidAmount, msg.sender, _originContract, _tokenId); | |
emit Bid(_originContract, msg.sender, _newBidAmount, _tokenId); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// safeAcceptBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Accept the bid on the token with the expected bid amount. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
* @param _amount uint256 wei amount of the bid | |
*/ | |
function safeAcceptBid( | |
address _originContract, | |
uint256 _tokenId, | |
uint256 _amount | |
) external { | |
// Make sure accepting bid is the expected amount | |
require( | |
tokenCurrentBids[_originContract][_tokenId].amount == _amount, | |
"safeAcceptBid::Bid amount must equal expected amount" | |
); | |
acceptBid(_originContract, _tokenId); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// acceptBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Accept the bid on the token. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token | |
*/ | |
function acceptBid(address _originContract, uint256 _tokenId) public { | |
// The owner of the token must have the marketplace approved | |
ownerMustHaveMarketplaceApproved(_originContract, _tokenId); | |
// The sender must be the token owner | |
senderMustBeTokenOwner(_originContract, _tokenId); | |
// Check that a bid exists. | |
require( | |
_tokenHasBid(_originContract, _tokenId), | |
"acceptBid::Cannot accept a bid when there is none." | |
); | |
// Get current bid on token | |
ActiveBid memory currentBid = | |
tokenCurrentBids[_originContract][_tokenId]; | |
// Wipe the token price and bid. | |
_resetTokenPrice(_originContract, _tokenId); | |
_resetBid(_originContract, _tokenId); | |
// Transfer token. | |
IERC721 erc721 = IERC721(_originContract); | |
erc721.safeTransferFrom(msg.sender, currentBid.bidder, _tokenId); | |
_distributeFees(msg.sender ,currentBid.amount); | |
emit AcceptBid( | |
_originContract, | |
currentBid.bidder, | |
msg.sender, | |
currentBid.amount, | |
_tokenId | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// cancelBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Cancel the bid on the token. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 ID of the token. | |
*/ | |
function cancelBid(address _originContract, uint256 _tokenId) external { | |
// Check that sender has a current bid. | |
require( | |
_addressHasBidOnToken(msg.sender, _originContract, _tokenId), | |
"cancelBid::Cannot cancel a bid if sender hasn't made one." | |
); | |
// Refund the bidder. | |
_refundBid(_originContract, _tokenId); | |
emit CancelBid( | |
_originContract, | |
msg.sender, | |
tokenCurrentBids[_originContract][_tokenId].amount, | |
_tokenId | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// currentBidDetailsOfToken | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Function to get current bid and bidder of a token. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function currentBidDetailsOfToken(address _originContract, uint256 _tokenId) | |
public | |
view | |
returns (uint256, address) | |
{ | |
return ( | |
tokenCurrentBids[_originContract][_tokenId].amount, | |
tokenCurrentBids[_originContract][_tokenId].bidder | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _priceSetterStillOwnsTheToken | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Checks that the token is owned by the same person who set the sale price. | |
* @param _originContract address of the contract storing the token. | |
* @param _tokenId uint256 id of the. | |
*/ | |
function _priceSetterStillOwnsTheToken( | |
address _originContract, | |
uint256 _tokenId | |
) internal view returns (bool) { | |
IERC721 erc721 = IERC721(_originContract); | |
return | |
erc721.ownerOf(_tokenId) == | |
tokenPrices[_originContract][_tokenId].seller; | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _resetTokenPrice | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to set token price to 0 for a given contract. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function _resetTokenPrice(address _originContract, uint256 _tokenId) | |
internal | |
{ | |
tokenPrices[_originContract][_tokenId] = SalePrice(address(0), 0); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _addressHasBidOnToken | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function see if the given address has an existing bid on a token. | |
* @param _bidder address that may have a current bid. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function _addressHasBidOnToken( | |
address _bidder, | |
address _originContract, | |
uint256 _tokenId | |
) internal view returns (bool) { | |
return tokenCurrentBids[_originContract][_tokenId].bidder == _bidder; | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _tokenHasBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function see if the token has an existing bid. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function _tokenHasBid(address _originContract, uint256 _tokenId) | |
internal | |
view | |
returns (bool) | |
{ | |
return tokenCurrentBids[_originContract][_tokenId].bidder != address(0); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _refundBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to return an existing bid on a token to the | |
* bidder and reset bid. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function _refundBid(address _originContract, uint256 _tokenId) internal { | |
ActiveBid memory currentBid = | |
tokenCurrentBids[_originContract][_tokenId]; | |
if (currentBid.bidder == address(0)) { | |
return; | |
} | |
_resetBid(_originContract, _tokenId); | |
Payments.refund( | |
currentBid.marketplaceFee, | |
currentBid.bidder, | |
currentBid.amount | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _resetBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to reset bid by setting bidder and bid to 0. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function _resetBid(address _originContract, uint256 _tokenId) internal { | |
tokenCurrentBids[_originContract][_tokenId] = ActiveBid( | |
address(0), | |
0, | |
0 | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _setBid | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to set a bid. | |
* @param _amount uint256 value in wei to bid. Does not include marketplace fee. | |
* @param _bidder address of the bidder. | |
* @param _originContract address of ERC721 contract. | |
* @param _tokenId uin256 id of the token. | |
*/ | |
function _setBid( | |
uint256 _amount, | |
address payable _bidder, | |
address _originContract, | |
uint256 _tokenId | |
) internal { | |
// Check bidder not 0 address. | |
require(_bidder != address(0), "Bidder cannot be 0 address."); | |
// Set bid. | |
tokenCurrentBids[_originContract][_tokenId] = ActiveBid( | |
_bidder, | |
0, | |
_amount | |
); | |
} | |
///////////////////////////////////////////////////////////////////////// | |
// _makePayable | |
///////////////////////////////////////////////////////////////////////// | |
/** | |
* @dev Internal function to set a bid. | |
* @param _address non-payable address | |
* @return payable address | |
*/ | |
function _makePayable(address _address) | |
internal | |
pure | |
returns (address payable) | |
{ | |
return address(uint160(_address)); | |
} | |
function _distributeFees(address _owner, uint256 amount) internal { | |
// Payout all parties. | |
uint256 paymentMarketPlace = calcPercentagePayment(amount, marketplacePercentage); | |
uint256 paymentMarketingTeam = calcPercentagePayment(paymentMarketPlace, marketingTeamPercentage); | |
uint256 paymentDevTeam = calcPercentagePayment(paymentMarketPlace, devTeamPercentage); | |
uint256 paymentCitizens = calcPercentagePayment(paymentMarketPlace, 10); | |
uint256 paymentPayee = (amount).sub(paymentMarketPlace).sub(100); | |
for(uint8 i = 0; i < 5; i++) { | |
address cityAddress = Village; | |
if(i == 0) { | |
cityAddress = Village; | |
} | |
else if(i == 1) { | |
cityAddress = County; | |
} | |
else if(i == 2) { | |
cityAddress = Town; | |
}else if(i == 3) { | |
cityAddress = Metropolis; | |
}else if(i == 4) { | |
cityAddress = MegaCity; | |
} | |
CryptoCityToken cityToken = CryptoCityToken(cityAddress); | |
address[] memory citizens = cityToken.getItems(); | |
uint256 eachShare = paymentCitizens.div(citizens.length); | |
for(uint8 j = 0; j < citizens.length; j++) { | |
if(eachShare > 0){ | |
Payments.simplePayout( | |
eachShare, | |
_makePayable(citizens[j]) | |
); | |
} | |
} | |
} | |
if(paymentMarketingTeam > 0){ | |
Payments.simplePayout( | |
paymentMarketingTeam, | |
_makePayable(marketingTeam) | |
); | |
} | |
if(paymentDevTeam > 0){ | |
Payments.simplePayout( | |
paymentDevTeam, | |
_makePayable(devTeam) | |
); | |
} | |
if(paymentPayee > 0){ | |
Payments.simplePayout( | |
paymentPayee, | |
_makePayable(_owner) | |
); | |
} | |
} | |
} |
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pragma solidity ^0.8.0; | |
// SPDX-License-Identifier: MIT | |
/** | |
* @dev Interface of the ERC165 standard, as defined in the | |
* https://eips.ethereum.org/EIPS/eip-165[EIP]. | |
* | |
* Implementers can declare support of contract interfaces, which can then be | |
* queried by others ({ERC165Checker}). | |
* | |
* For an implementation, see {ERC165}. | |
*/ | |
interface IERC165 { | |
/** | |
* @dev Returns true if this contract implements the interface defined by | |
* `interfaceId`. See the corresponding | |
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section] | |
* to learn more about how these ids are created. | |
* | |
* This function call must use less than 30 000 gas. | |
*/ | |
function supportsInterface(bytes4 interfaceId) external view returns (bool); | |
} | |
/** | |
* @dev Required interface of an ERC721 compliant contract. | |
*/ | |
interface IERC721 is IERC165 { | |
/** | |
* @dev Emitted when `tokenId` token is transferred from `from` to `to`. | |
*/ | |
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token. | |
*/ | |
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId); | |
/** | |
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets. | |
*/ | |
event ApprovalForAll(address indexed owner, address indexed operator, bool approved); | |
/** | |
* @dev Returns the number of tokens in ``owner``'s account. | |
*/ | |
function balanceOf(address owner) external view returns (uint256 balance); | |
/** | |
* @dev Returns the owner of the `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function ownerOf(uint256 tokenId) external view returns (address owner); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Transfers `tokenId` token from `from` to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) external; | |
/** | |
* @dev Gives permission to `to` to transfer `tokenId` token to another account. | |
* The approval is cleared when the token is transferred. | |
* | |
* Only a single account can be approved at a time, so approving the zero address clears previous approvals. | |
* | |
* Requirements: | |
* | |
* - The caller must own the token or be an approved operator. | |
* - `tokenId` must exist. | |
* | |
* Emits an {Approval} event. | |
*/ | |
function approve(address to, uint256 tokenId) external; | |
/** | |
* @dev Returns the account approved for `tokenId` token. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function getApproved(uint256 tokenId) external view returns (address operator); | |
/** | |
* @dev Approve or remove `operator` as an operator for the caller. | |
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller. | |
* | |
* Requirements: | |
* | |
* - The `operator` cannot be the caller. | |
* | |
* Emits an {ApprovalForAll} event. | |
*/ | |
function setApprovalForAll(address operator, bool _approved) external; | |
/** | |
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`. | |
* | |
* See {setApprovalForAll} | |
*/ | |
function isApprovedForAll(address owner, address operator) external view returns (bool); | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external; | |
} | |
/** | |
* @title ERC721 token receiver interface | |
* @dev Interface for any contract that wants to support safeTransfers | |
* from ERC721 asset contracts. | |
*/ | |
interface IERC721Receiver { | |
/** | |
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom} | |
* by `operator` from `from`, this function is called. | |
* | |
* It must return its Solidity selector to confirm the token transfer. | |
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted. | |
* | |
* The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`. | |
*/ | |
function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4); | |
} | |
/** | |
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension | |
* @dev See https://eips.ethereum.org/EIPS/eip-721 | |
*/ | |
interface IERC721Metadata is IERC721 { | |
/** | |
* @dev Returns the token collection name. | |
*/ | |
function name() external view returns (string memory); | |
/** | |
* @dev Returns the token collection symbol. | |
*/ | |
function symbol() external view returns (string memory); | |
/** | |
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token. | |
*/ | |
function tokenURI(uint256 tokenId) external view returns (string memory); | |
} | |
/** | |
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension | |
* @dev See https://eips.ethereum.org/EIPS/eip-721 | |
*/ | |
interface IERC721Enumerable is IERC721 { | |
/** | |
* @dev Returns the total amount of tokens stored by the contract. | |
*/ | |
function totalSupply() external view returns (uint256); | |
/** | |
* @dev Returns a token ID owned by `owner` at a given `index` of its token list. | |
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens. | |
*/ | |
function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId); | |
/** | |
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract. | |
* Use along with {totalSupply} to enumerate all tokens. | |
*/ | |
function tokenByIndex(uint256 index) external view returns (uint256); | |
} | |
abstract contract ERC165 is IERC165 { | |
/** | |
* @dev See {IERC165-supportsInterface}. | |
*/ | |
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) { | |
return interfaceId == type(IERC165).interfaceId; | |
} | |
} | |
/** | |
* @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; | |
// solhint-disable-next-line no-inline-assembly | |
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"); | |
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(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"); | |
// solhint-disable-next-line avoid-low-level-calls | |
(bool success, bytes memory returndata) = target.delegatecall(data); | |
return _verifyCallResult(success, returndata, errorMessage); | |
} | |
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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 | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
let returndata_size := mload(returndata) | |
revert(add(32, returndata), returndata_size) | |
} | |
} else { | |
revert(errorMessage); | |
} | |
} | |
} | |
} | |
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) { | |
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) { | |
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) { | |
// 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) { | |
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) { | |
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) { | |
uint256 c = a + b; | |
require(c >= a, "SafeMath: addition overflow"); | |
return c; | |
} | |
/** | |
* @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) { | |
require(b <= a, "SafeMath: subtraction overflow"); | |
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) { | |
if (a == 0) return 0; | |
uint256 c = a * b; | |
require(c / a == b, "SafeMath: multiplication overflow"); | |
return c; | |
} | |
/** | |
* @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. 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) internal pure returns (uint256) { | |
require(b > 0, "SafeMath: division by zero"); | |
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) { | |
require(b > 0, "SafeMath: modulo by zero"); | |
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) { | |
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. | |
* | |
* CAUTION: This function is deprecated because it requires allocating memory for the error | |
* message unnecessarily. For custom revert reasons use {tryDiv}. | |
* | |
* 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) { | |
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) { | |
require(b > 0, errorMessage); | |
return a % b; | |
} | |
} | |
abstract contract Context { | |
function _msgSender() internal view virtual returns (address) { | |
return msg.sender; | |
} | |
function _msgData() internal view virtual returns (bytes calldata) { | |
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691 | |
return msg.data; | |
} | |
} | |
/** | |
* @dev String operations. | |
*/ | |
library Strings { | |
bytes16 private constant alphabet = "0123456789abcdef"; | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` decimal representation. | |
*/ | |
function toString(uint256 value) internal pure returns (string memory) { | |
// Inspired by OraclizeAPI's implementation - MIT licence | |
// 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); | |
} | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation. | |
*/ | |
function toHexString(uint256 value) internal pure returns (string memory) { | |
if (value == 0) { | |
return "0x00"; | |
} | |
uint256 temp = value; | |
uint256 length = 0; | |
while (temp != 0) { | |
length++; | |
temp >>= 8; | |
} | |
return toHexString(value, length); | |
} | |
/** | |
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length. | |
*/ | |
function toHexString(uint256 value, uint256 length) internal pure returns (string memory) { | |
bytes memory buffer = new bytes(2 * length + 2); | |
buffer[0] = "0"; | |
buffer[1] = "x"; | |
for (uint256 i = 2 * length + 1; i > 1; --i) { | |
buffer[i] = alphabet[value & 0xf]; | |
value >>= 4; | |
} | |
require(value == 0, "Strings: hex length insufficient"); | |
return string(buffer); | |
} | |
} | |
/** | |
* @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;` | |
*/ | |
library Counters { | |
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 { | |
unchecked { | |
counter._value += 1; | |
} | |
} | |
function decrement(Counter storage counter) internal { | |
uint256 value = counter._value; | |
require(value > 0, "Counter: decrement overflow"); | |
unchecked { | |
counter._value = value - 1; | |
} | |
} | |
} | |
/** | |
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including | |
* the Metadata extension, but not including the Enumerable extension, which is available separately as | |
* {ERC721Enumerable}. | |
*/ | |
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata { | |
using Address for address; | |
using Strings for uint256; | |
// Token name | |
string private _name; | |
// Token symbol | |
string private _symbol; | |
// Mapping from token ID to owner address | |
mapping (uint256 => address) private _owners; | |
// Mapping owner address to token count | |
mapping (address => uint256) private _balances; | |
// Mapping from token ID to approved address | |
mapping (uint256 => address) private _tokenApprovals; | |
// Mapping from owner to operator approvals | |
mapping (address => mapping (address => bool)) private _operatorApprovals; | |
/** | |
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection. | |
*/ | |
constructor (string memory name_, string memory symbol_) { | |
_name = name_; | |
_symbol = symbol_; | |
} | |
/** | |
* @dev See {IERC165-supportsInterface}. | |
*/ | |
function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) { | |
return interfaceId == type(IERC721).interfaceId | |
|| interfaceId == type(IERC721Metadata).interfaceId | |
|| super.supportsInterface(interfaceId); | |
} | |
/** | |
* @dev See {IERC721-balanceOf}. | |
*/ | |
function balanceOf(address owner) public view virtual override returns (uint256) { | |
require(owner != address(0), "ERC721: balance query for the zero address"); | |
return _balances[owner]; | |
} | |
/** | |
* @dev See {IERC721-ownerOf}. | |
*/ | |
function ownerOf(uint256 tokenId) public view virtual override returns (address) { | |
address owner = _owners[tokenId]; | |
require(owner != address(0), "ERC721: owner query for nonexistent token"); | |
return owner; | |
} | |
/** | |
* @dev See {IERC721Metadata-name}. | |
*/ | |
function name() public view virtual override returns (string memory) { | |
return _name; | |
} | |
/** | |
* @dev See {IERC721Metadata-symbol}. | |
*/ | |
function symbol() public view virtual override returns (string memory) { | |
return _symbol; | |
} | |
/** | |
* @dev See {IERC721Metadata-tokenURI}. | |
*/ | |
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
string memory baseURI = _baseURI(); | |
return bytes(baseURI).length > 0 | |
? string(abi.encodePacked(baseURI, tokenId.toString())) | |
: ''; | |
} | |
/** | |
* @dev Base URI for computing {tokenURI}. Empty by default, can be overriden | |
* in child contracts. | |
*/ | |
function _baseURI() internal view virtual returns (string memory) { | |
return ""; | |
} | |
/** | |
* @dev See {IERC721-approve}. | |
*/ | |
function approve(address to, uint256 tokenId) public virtual override { | |
address owner = ERC721.ownerOf(tokenId); | |
require(to != owner, "ERC721: approval to current owner"); | |
require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()), | |
"ERC721: approve caller is not owner nor approved for all" | |
); | |
_approve(to, tokenId); | |
} | |
/** | |
* @dev See {IERC721-getApproved}. | |
*/ | |
function getApproved(uint256 tokenId) public view virtual override returns (address) { | |
require(_exists(tokenId), "ERC721: approved query for nonexistent token"); | |
return _tokenApprovals[tokenId]; | |
} | |
/** | |
* @dev See {IERC721-setApprovalForAll}. | |
*/ | |
function setApprovalForAll(address operator, bool approved) public virtual override { | |
require(operator != _msgSender(), "ERC721: approve to caller"); | |
_operatorApprovals[_msgSender()][operator] = approved; | |
emit ApprovalForAll(_msgSender(), operator, approved); | |
} | |
/** | |
* @dev See {IERC721-isApprovedForAll}. | |
*/ | |
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) { | |
return _operatorApprovals[owner][operator]; | |
} | |
/** | |
* @dev See {IERC721-transferFrom}. | |
*/ | |
function transferFrom(address from, address to, uint256 tokenId) public virtual override { | |
//solhint-disable-next-line max-line-length | |
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved"); | |
_transfer(from, to, tokenId); | |
} | |
/** | |
* @dev See {IERC721-safeTransferFrom}. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override { | |
safeTransferFrom(from, to, tokenId, ""); | |
} | |
/** | |
* @dev See {IERC721-safeTransferFrom}. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override { | |
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved"); | |
_safeTransfer(from, to, tokenId, _data); | |
} | |
/** | |
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients | |
* are aware of the ERC721 protocol to prevent tokens from being forever locked. | |
* | |
* `_data` is additional data, it has no specified format and it is sent in call to `to`. | |
* | |
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g. | |
* implement alternative mechanisms to perform token transfer, such as signature-based. | |
* | |
* Requirements: | |
* | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must exist and be owned by `from`. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual { | |
_transfer(from, to, tokenId); | |
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer"); | |
} | |
/** | |
* @dev Returns whether `tokenId` exists. | |
* | |
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}. | |
* | |
* Tokens start existing when they are minted (`_mint`), | |
* and stop existing when they are burned (`_burn`). | |
*/ | |
function _exists(uint256 tokenId) internal view virtual returns (bool) { | |
return _owners[tokenId] != address(0); | |
} | |
/** | |
* @dev Returns whether `spender` is allowed to manage `tokenId`. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
*/ | |
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) { | |
require(_exists(tokenId), "ERC721: operator query for nonexistent token"); | |
address owner = ERC721.ownerOf(tokenId); | |
return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender)); | |
} | |
/** | |
* @dev Safely mints `tokenId` and transfers it to `to`. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must not exist. | |
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _safeMint(address to, uint256 tokenId) internal virtual { | |
_safeMint(to, tokenId, ""); | |
} | |
/** | |
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is | |
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients. | |
*/ | |
function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual { | |
_mint(to, tokenId); | |
require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer"); | |
} | |
/** | |
* @dev Mints `tokenId` and transfers it to `to`. | |
* | |
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible | |
* | |
* Requirements: | |
* | |
* - `tokenId` must not exist. | |
* - `to` cannot be the zero address. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _mint(address to, uint256 tokenId) internal virtual { | |
require(to != address(0), "ERC721: mint to the zero address"); | |
require(!_exists(tokenId), "ERC721: token already minted"); | |
_beforeTokenTransfer(address(0), to, tokenId); | |
_balances[to] += 1; | |
_owners[tokenId] = to; | |
emit Transfer(address(0), to, tokenId); | |
} | |
/** | |
* @dev Destroys `tokenId`. | |
* The approval is cleared when the token is burned. | |
* | |
* Requirements: | |
* | |
* - `tokenId` must exist. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _burn(uint256 tokenId) internal virtual { | |
address owner = ERC721.ownerOf(tokenId); | |
_beforeTokenTransfer(owner, address(0), tokenId); | |
// Clear approvals | |
_approve(address(0), tokenId); | |
_balances[owner] -= 1; | |
delete _owners[tokenId]; | |
emit Transfer(owner, address(0), tokenId); | |
} | |
/** | |
* @dev Transfers `tokenId` from `from` to `to`. | |
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender. | |
* | |
* Requirements: | |
* | |
* - `to` cannot be the zero address. | |
* - `tokenId` token must be owned by `from`. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function _transfer(address from, address to, uint256 tokenId) internal virtual { | |
require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); | |
require(to != address(0), "ERC721: transfer to the zero address"); | |
_beforeTokenTransfer(from, to, tokenId); | |
// Clear approvals from the previous owner | |
_approve(address(0), tokenId); | |
_balances[from] -= 1; | |
_balances[to] += 1; | |
_owners[tokenId] = to; | |
emit Transfer(from, to, tokenId); | |
} | |
/** | |
* @dev Approve `to` to operate on `tokenId` | |
* | |
* Emits a {Approval} event. | |
*/ | |
function _approve(address to, uint256 tokenId) internal virtual { | |
_tokenApprovals[tokenId] = to; | |
emit Approval(ERC721.ownerOf(tokenId), to, tokenId); | |
} | |
/** | |
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address. | |
* The call is not executed if the target address is not a contract. | |
* | |
* @param from address representing the previous owner of the given token ID | |
* @param to target address that will receive the tokens | |
* @param tokenId uint256 ID of the token to be transferred | |
* @param _data bytes optional data to send along with the call | |
* @return bool whether the call correctly returned the expected magic value | |
*/ | |
function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data) | |
private returns (bool) | |
{ | |
if (to.isContract()) { | |
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) { | |
return retval == IERC721Receiver(to).onERC721Received.selector; | |
} catch (bytes memory reason) { | |
if (reason.length == 0) { | |
revert("ERC721: transfer to non ERC721Receiver implementer"); | |
} else { | |
// solhint-disable-next-line no-inline-assembly | |
assembly { | |
revert(add(32, reason), mload(reason)) | |
} | |
} | |
} | |
} else { | |
return true; | |
} | |
} | |
/** | |
* @dev Hook that is called before any token transfer. This includes minting | |
* and burning. | |
* | |
* Calling conditions: | |
* | |
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be | |
* transferred to `to`. | |
* - When `from` is zero, `tokenId` will be minted for `to`. | |
* - When `to` is zero, ``from``'s `tokenId` will be burned. | |
* - `from` cannot be the zero address. | |
* - `to` cannot be the zero address. | |
* | |
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks]. | |
*/ | |
function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { } | |
} | |
contract CryptoCityToken is ERC721 { | |
using Counters for Counters.Counter; | |
Counters.Counter private _tokenIds; | |
using SafeMath for uint256; | |
address payable public ownerContract; | |
///////////////////////////////////////////////////////////////////////////// | |
// Events | |
///////////////////////////////////////////////////////////////////////////// | |
constructor() ERC721("CryptoCity" , "CC"){ | |
ownerContract = payable(msg.sender); | |
} | |
struct Item { | |
uint256 id; | |
address creator; | |
string uri; | |
bool isCollection; | |
} | |
mapping (uint256 => Item) public Items; | |
function createItemOwner(string memory uri) public returns (uint256){ | |
require(_msgSender() == ownerContract , 'Only Owner'); | |
_tokenIds.increment(); | |
uint256 newItemId = _tokenIds.current(); | |
_safeMint(msg.sender, newItemId); | |
Items[newItemId] = Item(newItemId , msg.sender , uri, false); | |
return newItemId; | |
} | |
function createItem(string memory uri) public returns (uint256){ | |
_tokenIds.increment(); | |
uint256 newItemId = _tokenIds.current(); | |
_safeMint(msg.sender, newItemId); | |
Items[newItemId] = Item(newItemId , msg.sender , uri, false); | |
return newItemId; | |
} | |
function tokenURI(uint256 tokenId) public view override returns (string memory) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
return Items[tokenId].uri; | |
} | |
function getTokenCreator(uint256 tokenId) external view returns (address) { | |
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token"); | |
return Items[tokenId].creator; | |
} | |
function getItem(uint256 tokenId) external view returns (Item memory) { | |
return Items[tokenId]; | |
} | |
} |
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