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ERC-721
Overview
Max Total Supply
235 LOTTO
Holders
234
Market
Volume (24H)
N/A
Min Price (24H)
N/A
Max Price (24H)
N/A
Other Info
Token Contract
Balance
1 LOTTOLoading...
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# | Exchange | Pair | Price | 24H Volume | % Volume |
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Minimal Proxy Contract for 0x19dd2b11b886a88aecf30f1c804e86c4daf4cd87
Contract Name:
NFTLotteryPool
Compiler Version
v0.6.8+commit.0bbfe453
Contract Source Code (Solidity)
/** *Submitted for verification at Etherscan.io on 2021-08-12 */ // File: @openzeppelin/contracts/utils/ReentrancyGuard.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @dev Contract module that helps prevent reentrant calls to a function. * * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier * available, which can be applied to functions to make sure there are no nested * (reentrant) calls to them. * * Note that because there is a single `nonReentrant` guard, functions marked as * `nonReentrant` may not call one another. This can be worked around by making * those functions `private`, and then adding `external` `nonReentrant` entry * points to them. * * TIP: If you would like to learn more about reentrancy and alternative ways * to protect against it, check out our blog post * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul]. */ contract ReentrancyGuard { // Booleans are more expensive than uint256 or any type that takes up a full // word because each write operation emits an extra SLOAD to first read the // slot's contents, replace the bits taken up by the boolean, and then write // back. This is the compiler's defense against contract upgrades and // pointer aliasing, and it cannot be disabled. // The values being non-zero value makes deployment a bit more expensive, // but in exchange the refund on every call to nonReentrant will be lower in // amount. Since refunds are capped to a percentage of the total // transaction's gas, it is best to keep them low in cases like this one, to // increase the likelihood of the full refund coming into effect. uint256 private constant _NOT_ENTERED = 1; uint256 private constant _ENTERED = 2; uint256 private _status; constructor () internal { _status = _NOT_ENTERED; } /** * @dev Prevents a contract from calling itself, directly or indirectly. * Calling a `nonReentrant` function from another `nonReentrant` * function is not supported. It is possible to prevent this from happening * by making the `nonReentrant` function external, and make it call a * `private` function that does the actual work. */ modifier nonReentrant() { // On the first call to nonReentrant, _notEntered will be true require(_status != _ENTERED, "ReentrancyGuard: reentrant call"); // Any calls to nonReentrant after this point will fail _status = _ENTERED; _; // By storing the original value once again, a refund is triggered (see // https://eips.ethereum.org/EIPS/eip-2200) _status = _NOT_ENTERED; } } // File: @openzeppelin/contracts/token/ERC20/IERC20.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @dev Interface of the ERC20 standard as defined in the EIP. */ interface IERC20 { /** * @dev Returns the amount of tokens in existence. */ function totalSupply() external view returns (uint256); /** * @dev Returns the amount of tokens owned by `account`. */ function balanceOf(address account) external view returns (uint256); /** * @dev Moves `amount` tokens from the caller's account to `recipient`. * * Returns a boolean value indicating whether the operation succeeded. * * Emits a {Transfer} event. */ function transfer(address recipient, uint256 amount) external returns (bool); /** * @dev Returns the remaining number of tokens that `spender` will be * allowed to spend on behalf of `owner` through {transferFrom}. This is * zero by default. * * This value changes when {approve} or {transferFrom} are called. */ function allowance(address owner, address spender) external view returns (uint256); /** * @dev Sets `amount` as the allowance of `spender` over the caller's tokens. * * Returns a boolean value indicating whether the operation succeeded. * * IMPORTANT: Beware that changing an allowance with this method brings the risk * that someone may use both the old and the new allowance by unfortunate * transaction ordering. One possible solution to mitigate this race * condition is to first reduce the spender's allowance to 0 and set the * desired value afterwards: * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729 * * Emits an {Approval} event. */ function approve(address spender, uint256 amount) external returns (bool); /** * @dev Moves `amount` tokens from `sender` to `recipient` using the * allowance mechanism. `amount` is then deducted from the caller's * allowance. * * Returns a boolean value indicating whether the operation succeeded. * * Emits a {Transfer} event. */ function transferFrom(address sender, address recipient, uint256 amount) external returns (bool); /** * @dev Emitted when `value` tokens are moved from one account (`from`) to * another (`to`). * * Note that `value` may be zero. */ event Transfer(address indexed from, address indexed to, uint256 value); /** * @dev Emitted when the allowance of a `spender` for an `owner` is set by * a call to {approve}. `value` is the new allowance. */ event Approval(address indexed owner, address indexed spender, uint256 value); } // File: @openzeppelin/contracts/math/SafeMath.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @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 SafeMath { /** * @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; } } // File: @openzeppelin/contracts/utils/Address.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.2; /** * @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 in 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"); return _functionCallWithValue(target, data, value, errorMessage); } function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) { require(isContract(target), "Address: call to non-contract"); // solhint-disable-next-line avoid-low-level-calls (bool success, bytes memory returndata) = target.call{ value: weiValue }(data); 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); } } } } // File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @title SafeERC20 * @dev Wrappers around ERC20 operations that throw on failure (when the token * contract returns false). Tokens that return no value (and instead revert or * throw on failure) are also supported, non-reverting calls are assumed to be * successful. * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract, * which allows you to call the safe operations as `token.safeTransfer(...)`, etc. */ library SafeERC20 { using SafeMath for uint256; using Address for address; function safeTransfer(IERC20 token, address to, uint256 value) internal { _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value)); } function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal { _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value)); } /** * @dev Deprecated. This function has issues similar to the ones found in * {IERC20-approve}, and its usage is discouraged. * * Whenever possible, use {safeIncreaseAllowance} and * {safeDecreaseAllowance} instead. */ function safeApprove(IERC20 token, address spender, uint256 value) internal { // safeApprove should only be called when setting an initial allowance, // or when resetting it to zero. To increase and decrease it, use // 'safeIncreaseAllowance' and 'safeDecreaseAllowance' // solhint-disable-next-line max-line-length require((value == 0) || (token.allowance(address(this), spender) == 0), "SafeERC20: approve from non-zero to non-zero allowance" ); _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value)); } function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).add(value); _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance)); } function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero"); _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance)); } /** * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement * on the return value: the return value is optional (but if data is returned, it must not be false). * @param token The token targeted by the call. * @param data The call data (encoded using abi.encode or one of its variants). */ function _callOptionalReturn(IERC20 token, bytes memory data) private { // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that // the target address contains contract code and also asserts for success in the low-level call. bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed"); if (returndata.length > 0) { // Return data is optional // solhint-disable-next-line max-line-length require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed"); } } } // File: @openzeppelin/contracts/introspection/IERC165.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @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); } // File: @openzeppelin/contracts/token/ERC721/IERC721.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.2; /** * @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; } // File: @openzeppelin/contracts/token/ERC721/IERC721Enumerable.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.2; /** * @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); } // File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @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); } // File: @openzeppelin/contracts/token/ERC721/ERC721Holder.sol // SPD-License-Identifier: MIT pragma solidity ^0.6.0; /** * @dev Implementation of the {IERC721Receiver} interface. * * Accepts all token transfers. * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or {IERC721-setApprovalForAll}. */ contract ERC721Holder is IERC721Receiver { /** * @dev See {IERC721Receiver-onERC721Received}. * * Always returns `IERC721Receiver.onERC721Received.selector`. */ function onERC721Received(address, address, uint256, bytes memory) public virtual override returns (bytes4) { return this.onERC721Received.selector; } } // File: @openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.2 <0.8.0; /** * @dev Collection of functions related to the address type */ 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); } } } } // File: @openzeppelin/contracts-upgradeable/proxy/Initializable.sol // SPD-License-Identifier: MIT // solhint-disable-next-line compiler-version pragma solidity >=0.4.24 <0.8.0; /** * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect. * * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}. * * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity. */ 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) { return !AddressUpgradeable.isContract(address(this)); } } // File: @openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /* * @dev Provides information about the current execution context, including the * sender of the transaction and its data. While these are generally available * via msg.sender and msg.data, they should not be accessed in such a direct * manner, since when dealing with GSN meta-transactions the account sending and * paying for execution may not be the actual sender (as far as an application * is concerned). * * This contract is only required for intermediate, library-like contracts. */ abstract contract 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; } // File: @openzeppelin/contracts-upgradeable/introspection/IERC165Upgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @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 IERC165Upgradeable { /** * @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); } // File: @openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.2 <0.8.0; /** * @dev Required interface of an ERC721 compliant contract. */ interface IERC721Upgradeable is IERC165Upgradeable { /** * @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; } // File: @openzeppelin/contracts-upgradeable/token/ERC721/IERC721MetadataUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.2 <0.8.0; /** * @title ERC-721 Non-Fungible Token Standard, optional metadata extension * @dev See https://eips.ethereum.org/EIPS/eip-721 */ interface IERC721MetadataUpgradeable is IERC721Upgradeable { /** * @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); } // File: @openzeppelin/contracts-upgradeable/token/ERC721/IERC721EnumerableUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.2 <0.8.0; /** * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension * @dev See https://eips.ethereum.org/EIPS/eip-721 */ interface IERC721EnumerableUpgradeable is IERC721Upgradeable { /** * @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); } // File: @openzeppelin/contracts-upgradeable/token/ERC721/IERC721ReceiverUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @title ERC721 token receiver interface * @dev Interface for any contract that wants to support safeTransfers * from ERC721 asset contracts. */ interface IERC721ReceiverUpgradeable { /** * @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); } // File: @openzeppelin/contracts-upgradeable/introspection/ERC165Upgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @dev Implementation of the {IERC165} interface. * * Contracts may inherit from this and call {_registerInterface} to declare * their support of an interface. */ abstract contract ERC165Upgradeable is Initializable, IERC165Upgradeable { /* * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7 */ bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7; /** * @dev Mapping of interface ids to whether or not it's supported. */ mapping(bytes4 => bool) private _supportedInterfaces; function __ERC165_init() internal initializer { __ERC165_init_unchained(); } function __ERC165_init_unchained() internal initializer { // Derived contracts need only register support for their own interfaces, // we register support for ERC165 itself here _registerInterface(_INTERFACE_ID_ERC165); } /** * @dev See {IERC165-supportsInterface}. * * Time complexity O(1), guaranteed to always use less than 30 000 gas. */ function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) { return _supportedInterfaces[interfaceId]; } /** * @dev Registers the contract as an implementer of the interface defined by * `interfaceId`. Support of the actual ERC165 interface is automatic and * registering its interface id is not required. * * See {IERC165-supportsInterface}. * * Requirements: * * - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`). */ function _registerInterface(bytes4 interfaceId) internal virtual { require(interfaceId != 0xffffffff, "ERC165: invalid interface id"); _supportedInterfaces[interfaceId] = true; } uint256[49] private __gap; } // File: @openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @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, 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; } } // File: @openzeppelin/contracts-upgradeable/utils/EnumerableSetUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @dev Library for managing * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive * types. * * Sets have the following properties: * * - Elements are added, removed, and checked for existence in constant time * (O(1)). * - Elements are enumerated in O(n). No guarantees are made on the ordering. * * ``` * contract Example { * // Add the library methods * using EnumerableSet for EnumerableSet.AddressSet; * * // Declare a set state variable * EnumerableSet.AddressSet private mySet; * } * ``` * * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`) * and `uint256` (`UintSet`) are supported. */ library EnumerableSetUpgradeable { // To implement this library for multiple types with as little code // repetition as possible, we write it in terms of a generic Set type with // bytes32 values. // The Set implementation uses private functions, and user-facing // implementations (such as AddressSet) are just wrappers around the // underlying Set. // This means that we can only create new EnumerableSets for types that fit // in bytes32. struct Set { // Storage of set values bytes32[] _values; // Position of the value in the `values` array, plus 1 because index 0 // means a value is not in the set. mapping (bytes32 => uint256) _indexes; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function _add(Set storage set, bytes32 value) private returns (bool) { if (!_contains(set, value)) { set._values.push(value); // The value is stored at length-1, but we add 1 to all indexes // and use 0 as a sentinel value set._indexes[value] = set._values.length; return true; } else { return false; } } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function _remove(Set storage set, bytes32 value) private returns (bool) { // We read and store the value's index to prevent multiple reads from the same storage slot uint256 valueIndex = set._indexes[value]; if (valueIndex != 0) { // Equivalent to contains(set, value) // To delete an element from the _values array in O(1), we swap the element to delete with the last one in // the array, and then remove the last element (sometimes called as 'swap and pop'). // This modifies the order of the array, as noted in {at}. uint256 toDeleteIndex = valueIndex - 1; uint256 lastIndex = set._values.length - 1; // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement. bytes32 lastvalue = set._values[lastIndex]; // Move the last value to the index where the value to delete is set._values[toDeleteIndex] = lastvalue; // Update the index for the moved value set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based // Delete the slot where the moved value was stored set._values.pop(); // Delete the index for the deleted slot delete set._indexes[value]; return true; } else { return false; } } /** * @dev Returns true if the value is in the set. O(1). */ function _contains(Set storage set, bytes32 value) private view returns (bool) { return set._indexes[value] != 0; } /** * @dev Returns the number of values on the set. O(1). */ function _length(Set storage set) private view returns (uint256) { return set._values.length; } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function _at(Set storage set, uint256 index) private view returns (bytes32) { require(set._values.length > index, "EnumerableSet: index out of bounds"); return set._values[index]; } // Bytes32Set struct Bytes32Set { Set _inner; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function add(Bytes32Set storage set, bytes32 value) internal returns (bool) { return _add(set._inner, value); } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) { return _remove(set._inner, value); } /** * @dev Returns true if the value is in the set. O(1). */ function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) { return _contains(set._inner, value); } /** * @dev Returns the number of values in the set. O(1). */ function length(Bytes32Set storage set) internal view returns (uint256) { return _length(set._inner); } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) { return _at(set._inner, index); } // AddressSet struct AddressSet { Set _inner; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function add(AddressSet storage set, address value) internal returns (bool) { return _add(set._inner, bytes32(uint256(uint160(value)))); } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function remove(AddressSet storage set, address value) internal returns (bool) { return _remove(set._inner, bytes32(uint256(uint160(value)))); } /** * @dev Returns true if the value is in the set. O(1). */ function contains(AddressSet storage set, address value) internal view returns (bool) { return _contains(set._inner, bytes32(uint256(uint160(value)))); } /** * @dev Returns the number of values in the set. O(1). */ function length(AddressSet storage set) internal view returns (uint256) { return _length(set._inner); } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(AddressSet storage set, uint256 index) internal view returns (address) { return address(uint160(uint256(_at(set._inner, index)))); } // UintSet struct UintSet { Set _inner; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function add(UintSet storage set, uint256 value) internal returns (bool) { return _add(set._inner, bytes32(value)); } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function remove(UintSet storage set, uint256 value) internal returns (bool) { return _remove(set._inner, bytes32(value)); } /** * @dev Returns true if the value is in the set. O(1). */ function contains(UintSet storage set, uint256 value) internal view returns (bool) { return _contains(set._inner, bytes32(value)); } /** * @dev Returns the number of values on the set. O(1). */ function length(UintSet storage set) internal view returns (uint256) { return _length(set._inner); } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(UintSet storage set, uint256 index) internal view returns (uint256) { return uint256(_at(set._inner, index)); } } // File: @openzeppelin/contracts-upgradeable/utils/EnumerableMapUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @dev Library for managing an enumerable variant of Solidity's * https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`] * type. * * Maps have the following properties: * * - Entries are added, removed, and checked for existence in constant time * (O(1)). * - Entries are enumerated in O(n). No guarantees are made on the ordering. * * ``` * contract Example { * // Add the library methods * using EnumerableMap for EnumerableMap.UintToAddressMap; * * // Declare a set state variable * EnumerableMap.UintToAddressMap private myMap; * } * ``` * * As of v3.0.0, only maps of type `uint256 -> address` (`UintToAddressMap`) are * supported. */ library EnumerableMapUpgradeable { // To implement this library for multiple types with as little code // repetition as possible, we write it in terms of a generic Map type with // bytes32 keys and values. // The Map implementation uses private functions, and user-facing // implementations (such as Uint256ToAddressMap) are just wrappers around // the underlying Map. // This means that we can only create new EnumerableMaps for types that fit // in bytes32. struct MapEntry { bytes32 _key; bytes32 _value; } struct Map { // Storage of map keys and values MapEntry[] _entries; // Position of the entry defined by a key in the `entries` array, plus 1 // because index 0 means a key is not in the map. mapping (bytes32 => uint256) _indexes; } /** * @dev Adds a key-value pair to a map, or updates the value for an existing * key. O(1). * * Returns true if the key was added to the map, that is if it was not * already present. */ function _set(Map storage map, bytes32 key, bytes32 value) private returns (bool) { // We read and store the key's index to prevent multiple reads from the same storage slot uint256 keyIndex = map._indexes[key]; if (keyIndex == 0) { // Equivalent to !contains(map, key) map._entries.push(MapEntry({ _key: key, _value: value })); // The entry is stored at length-1, but we add 1 to all indexes // and use 0 as a sentinel value map._indexes[key] = map._entries.length; return true; } else { map._entries[keyIndex - 1]._value = value; return false; } } /** * @dev Removes a key-value pair from a map. O(1). * * Returns true if the key was removed from the map, that is if it was present. */ function _remove(Map storage map, bytes32 key) private returns (bool) { // We read and store the key's index to prevent multiple reads from the same storage slot uint256 keyIndex = map._indexes[key]; if (keyIndex != 0) { // Equivalent to contains(map, key) // To delete a key-value pair from the _entries array in O(1), we swap the entry to delete with the last one // in the array, and then remove the last entry (sometimes called as 'swap and pop'). // This modifies the order of the array, as noted in {at}. uint256 toDeleteIndex = keyIndex - 1; uint256 lastIndex = map._entries.length - 1; // When the entry to delete is the last one, the swap operation is unnecessary. However, since this occurs // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement. MapEntry storage lastEntry = map._entries[lastIndex]; // Move the last entry to the index where the entry to delete is map._entries[toDeleteIndex] = lastEntry; // Update the index for the moved entry map._indexes[lastEntry._key] = toDeleteIndex + 1; // All indexes are 1-based // Delete the slot where the moved entry was stored map._entries.pop(); // Delete the index for the deleted slot delete map._indexes[key]; return true; } else { return false; } } /** * @dev Returns true if the key is in the map. O(1). */ function _contains(Map storage map, bytes32 key) private view returns (bool) { return map._indexes[key] != 0; } /** * @dev Returns the number of key-value pairs in the map. O(1). */ function _length(Map storage map) private view returns (uint256) { return map._entries.length; } /** * @dev Returns the key-value pair stored at position `index` in the map. O(1). * * Note that there are no guarantees on the ordering of entries inside the * array, and it may change when more entries are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function _at(Map storage map, uint256 index) private view returns (bytes32, bytes32) { require(map._entries.length > index, "EnumerableMap: index out of bounds"); MapEntry storage entry = map._entries[index]; return (entry._key, entry._value); } /** * @dev Tries to returns the value associated with `key`. O(1). * Does not revert if `key` is not in the map. */ function _tryGet(Map storage map, bytes32 key) private view returns (bool, bytes32) { uint256 keyIndex = map._indexes[key]; if (keyIndex == 0) return (false, 0); // Equivalent to contains(map, key) return (true, map._entries[keyIndex - 1]._value); // All indexes are 1-based } /** * @dev Returns the value associated with `key`. O(1). * * Requirements: * * - `key` must be in the map. */ function _get(Map storage map, bytes32 key) private view returns (bytes32) { uint256 keyIndex = map._indexes[key]; require(keyIndex != 0, "EnumerableMap: nonexistent key"); // Equivalent to contains(map, key) return map._entries[keyIndex - 1]._value; // All indexes are 1-based } /** * @dev Same as {_get}, with a custom error message when `key` is not in the map. * * CAUTION: This function is deprecated because it requires allocating memory for the error * message unnecessarily. For custom revert reasons use {_tryGet}. */ function _get(Map storage map, bytes32 key, string memory errorMessage) private view returns (bytes32) { uint256 keyIndex = map._indexes[key]; require(keyIndex != 0, errorMessage); // Equivalent to contains(map, key) return map._entries[keyIndex - 1]._value; // All indexes are 1-based } // UintToAddressMap struct UintToAddressMap { Map _inner; } /** * @dev Adds a key-value pair to a map, or updates the value for an existing * key. O(1). * * Returns true if the key was added to the map, that is if it was not * already present. */ function set(UintToAddressMap storage map, uint256 key, address value) internal returns (bool) { return _set(map._inner, bytes32(key), bytes32(uint256(uint160(value)))); } /** * @dev Removes a value from a set. O(1). * * Returns true if the key was removed from the map, that is if it was present. */ function remove(UintToAddressMap storage map, uint256 key) internal returns (bool) { return _remove(map._inner, bytes32(key)); } /** * @dev Returns true if the key is in the map. O(1). */ function contains(UintToAddressMap storage map, uint256 key) internal view returns (bool) { return _contains(map._inner, bytes32(key)); } /** * @dev Returns the number of elements in the map. O(1). */ function length(UintToAddressMap storage map) internal view returns (uint256) { return _length(map._inner); } /** * @dev Returns the element stored at position `index` in the set. O(1). * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(UintToAddressMap storage map, uint256 index) internal view returns (uint256, address) { (bytes32 key, bytes32 value) = _at(map._inner, index); return (uint256(key), address(uint160(uint256(value)))); } /** * @dev Tries to returns the value associated with `key`. O(1). * Does not revert if `key` is not in the map. * * _Available since v3.4._ */ function tryGet(UintToAddressMap storage map, uint256 key) internal view returns (bool, address) { (bool success, bytes32 value) = _tryGet(map._inner, bytes32(key)); return (success, address(uint160(uint256(value)))); } /** * @dev Returns the value associated with `key`. O(1). * * Requirements: * * - `key` must be in the map. */ function get(UintToAddressMap storage map, uint256 key) internal view returns (address) { return address(uint160(uint256(_get(map._inner, bytes32(key))))); } /** * @dev Same as {get}, with a custom error message when `key` is not in the map. * * CAUTION: This function is deprecated because it requires allocating memory for the error * message unnecessarily. For custom revert reasons use {tryGet}. */ function get(UintToAddressMap storage map, uint256 key, string memory errorMessage) internal view returns (address) { return address(uint160(uint256(_get(map._inner, bytes32(key), errorMessage)))); } } // File: @openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @dev String operations. */ library StringsUpgradeable { /** * @dev Converts a `uint256` to its ASCII `string` 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); uint256 index = digits - 1; temp = value; while (temp != 0) { buffer[index--] = bytes1(uint8(48 + temp % 10)); temp /= 10; } return string(buffer); } } // File: @openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @title ERC721 Non-Fungible Token Standard basic implementation * @dev see https://eips.ethereum.org/EIPS/eip-721 */ contract ERC721Upgradeable is Initializable, ContextUpgradeable, ERC165Upgradeable, IERC721Upgradeable, IERC721MetadataUpgradeable, IERC721EnumerableUpgradeable { using SafeMathUpgradeable for uint256; using AddressUpgradeable for address; using EnumerableSetUpgradeable for EnumerableSetUpgradeable.UintSet; using EnumerableMapUpgradeable for EnumerableMapUpgradeable.UintToAddressMap; using StringsUpgradeable for uint256; // Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))` // which can be also obtained as `IERC721Receiver(0).onERC721Received.selector` bytes4 private constant _ERC721_RECEIVED = 0x150b7a02; // Mapping from holder address to their (enumerable) set of owned tokens mapping (address => EnumerableSetUpgradeable.UintSet) private _holderTokens; // Enumerable mapping from token ids to their owners EnumerableMapUpgradeable.UintToAddressMap private _tokenOwners; // 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; // Token name string private _name; // Token symbol string private _symbol; // Optional mapping for token URIs mapping (uint256 => string) private _tokenURIs; // Base URI string private _baseURI; /* * bytes4(keccak256('balanceOf(address)')) == 0x70a08231 * bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e * bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3 * bytes4(keccak256('getApproved(uint256)')) == 0x081812fc * bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465 * bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5 * bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd * bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e * bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde * * => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^ * 0xa22cb465 ^ 0xe985e9c5 ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd */ bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd; /* * bytes4(keccak256('name()')) == 0x06fdde03 * bytes4(keccak256('symbol()')) == 0x95d89b41 * bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd * * => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f */ bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f; /* * bytes4(keccak256('totalSupply()')) == 0x18160ddd * bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59 * bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7 * * => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63 */ bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63; /** * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection. */ function __ERC721_init(string memory name_, string memory symbol_) internal initializer { __Context_init_unchained(); __ERC165_init_unchained(); __ERC721_init_unchained(name_, symbol_); } function __ERC721_init_unchained(string memory name_, string memory symbol_) internal initializer { _name = name_; _symbol = symbol_; // register the supported interfaces to conform to ERC721 via ERC165 _registerInterface(_INTERFACE_ID_ERC721); _registerInterface(_INTERFACE_ID_ERC721_METADATA); _registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE); } /** * @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 _holderTokens[owner].length(); } /** * @dev See {IERC721-ownerOf}. */ function ownerOf(uint256 tokenId) public view virtual override returns (address) { return _tokenOwners.get(tokenId, "ERC721: owner query for nonexistent token"); } /** * @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 _tokenURI = _tokenURIs[tokenId]; string memory base = baseURI(); // If there is no base URI, return the token URI. if (bytes(base).length == 0) { return _tokenURI; } // If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked). if (bytes(_tokenURI).length > 0) { return string(abi.encodePacked(base, _tokenURI)); } // If there is a baseURI but no tokenURI, concatenate the tokenID to the baseURI. return string(abi.encodePacked(base, tokenId.toString())); } /** * @dev Returns the base URI set via {_setBaseURI}. This will be * automatically added as a prefix in {tokenURI} to each token's URI, or * to the token ID if no specific URI is set for that token ID. */ function baseURI() public view virtual returns (string memory) { return _baseURI; } /** * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}. */ function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) { return _holderTokens[owner].at(index); } /** * @dev See {IERC721Enumerable-totalSupply}. */ function totalSupply() public view virtual override returns (uint256) { // _tokenOwners are indexed by tokenIds, so .length() returns the number of tokenIds return _tokenOwners.length(); } /** * @dev See {IERC721Enumerable-tokenByIndex}. */ function tokenByIndex(uint256 index) public view virtual override returns (uint256) { (uint256 tokenId, ) = _tokenOwners.at(index); return tokenId; } /** * @dev See {IERC721-approve}. */ function approve(address to, uint256 tokenId) public virtual override { address owner = ERC721Upgradeable.ownerOf(tokenId); require(to != owner, "ERC721: approval to current owner"); require(_msgSender() == owner || ERC721Upgradeable.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 _tokenOwners.contains(tokenId); } /** * @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 = ERC721Upgradeable.ownerOf(tokenId); return (spender == owner || getApproved(tokenId) == spender || ERC721Upgradeable.isApprovedForAll(owner, spender)); } /** * @dev Safely mints `tokenId` and transfers it to `to`. * * Requirements: d* * - `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); _holderTokens[to].add(tokenId); _tokenOwners.set(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 = ERC721Upgradeable.ownerOf(tokenId); // internal owner _beforeTokenTransfer(owner, address(0), tokenId); // Clear approvals _approve(address(0), tokenId); // Clear metadata (if any) if (bytes(_tokenURIs[tokenId]).length != 0) { delete _tokenURIs[tokenId]; } _holderTokens[owner].remove(tokenId); _tokenOwners.remove(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(ERC721Upgradeable.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); // internal owner require(to != address(0), "ERC721: transfer to the zero address"); _beforeTokenTransfer(from, to, tokenId); // Clear approvals from the previous owner _approve(address(0), tokenId); _holderTokens[from].remove(tokenId); _holderTokens[to].add(tokenId); _tokenOwners.set(tokenId, to); emit Transfer(from, to, tokenId); } /** * @dev Sets `_tokenURI` as the tokenURI of `tokenId`. * * Requirements: * * - `tokenId` must exist. */ function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual { require(_exists(tokenId), "ERC721Metadata: URI set of nonexistent token"); _tokenURIs[tokenId] = _tokenURI; } /** * @dev Internal function to set the base URI for all token IDs. It is * automatically added as a prefix to the value returned in {tokenURI}, * or to the token ID if {tokenURI} is empty. */ function _setBaseURI(string memory baseURI_) internal virtual { _baseURI = baseURI_; } /** * @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()) { return true; } bytes memory returndata = to.functionCall(abi.encodeWithSelector( IERC721ReceiverUpgradeable(to).onERC721Received.selector, _msgSender(), from, tokenId, _data ), "ERC721: transfer to non ERC721Receiver implementer"); bytes4 retval = abi.decode(returndata, (bytes4)); return (retval == _ERC721_RECEIVED); } /** * @dev Approve `to` to operate on `tokenId` * * Emits an {Approval} event. */ function _approve(address to, uint256 tokenId) internal virtual { _tokenApprovals[tokenId] = to; emit Approval(ERC721Upgradeable.ownerOf(tokenId), to, tokenId); // internal owner } /** * @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 { } uint256[41] private __gap; } // File: @openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol // SPD-License-Identifier: MIT pragma solidity >=0.6.0 <0.8.0; /** * @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 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 virtual returns (address) { return _owner; } /** * @dev Throws if called by any account other than the owner. */ modifier onlyOwner() { require(owner() == _msgSender(), "Ownable: caller is not the owner"); _; } /** * @dev Leaves the contract without owner. It will not be possible to call * `onlyOwner` functions anymore. Can only be called by the current owner. * * NOTE: Renouncing ownership will leave the contract without an owner, * thereby removing any functionality that is only available to the owner. */ function renounceOwnership() public virtual onlyOwner { 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; } // File: contracts/IDistributor.sol // SPD-License-Identifier: AGPL-3.0-or-later pragma solidity ^0.6.8; interface IDistributor { function distributeToNftHolders( uint256 fee, address _nftRecipientAddress, uint256 startIndex, uint256 endIndex, address _rewardAddress, uint256 _rewardId ) external; } // File: contracts/ILotteryReference.sol // SPD-License-Identifier: AGPL-3.0-or-later pragma solidity ^0.6.8; interface ILotteryReference { function LINK_ADDRESS() external returns(address); function RNG_DISTRIBUTOR_ADDRESS() external returns(address); function LINK_FEE() external returns(uint256); function masterTokenURI() external view returns (address); } // File: contracts/ITokenURI.sol // SPD-License-Identifier: AGPL-3.0-or-later pragma solidity ^0.6.8; interface ITokenURI { function tokenURI(uint256 id) external view returns (string memory); } // File: contracts/NFTLotteryPool.sol // SPD-License-Identifier: AGPL-3.0-or-later pragma solidity ^0.6.8; contract NFTLotteryPool is ERC721Upgradeable, OwnableUpgradeable, ERC721Holder, ReentrancyGuard { using SafeERC20 for IERC20; ILotteryReference private REFERENCE; IDistributor private RNG_DISTRIBUTOR; IERC20 private LINK; // Lottery vars address public prizeAddress; uint256 public prizeId; uint64 public startDate; uint64 public endDate; uint32 public minTicketsToSell; uint32 public maxTickets; uint32 public maxTicketsPerAddress; uint256 public ticketPrice; // Mutex for calling VRF bool public hasCalledVRF; // Check if refunds are allowed bool public isRefundOpen; function initialize( address _prizeAddress, uint256 _prizeId, uint64 _startDate, uint64 _endDate, uint32 _minTicketsToSell, uint32 _maxTickets, uint32 _maxTicketsPerAddress, uint256 _ticketPrice ) external initializer { require(_endDate > _startDate, "End is before start"); require(_minTicketsToSell > 0, "Min sell at least 1"); require(_minTicketsToSell <= _maxTickets, "Min greater than max"); require(_maxTicketsPerAddress >= 1, "Must be able to buy at least 1"); __Ownable_init(); __ERC721_init("NFT-LOTTERY", "LOTTO"); REFERENCE = ILotteryReference(msg.sender); LINK = IERC20(REFERENCE.LINK_ADDRESS()); RNG_DISTRIBUTOR = IDistributor(REFERENCE.RNG_DISTRIBUTOR_ADDRESS()); prizeAddress = _prizeAddress; prizeId = _prizeId; startDate = _startDate; endDate = _endDate; minTicketsToSell = _minTicketsToSell; maxTickets = _maxTickets; maxTicketsPerAddress = _maxTicketsPerAddress; ticketPrice = _ticketPrice; // NOTE: Prize and LINK are moved into the contract via the pool factory } function buyTickets(uint256 numTickets) public payable { require(block.timestamp >= startDate, "Too early"); require(balanceOf(msg.sender).add(numTickets) <= maxTicketsPerAddress, "Holding too many"); require(totalSupply().add(numTickets) <= maxTickets, "Exceeds max supply"); require(msg.value == ticketPrice.mul(numTickets), "Price incorrect"); require(block.timestamp < endDate, "Lottery over"); for (uint256 i = 0; i < numTickets; i++) { _mint(msg.sender, totalSupply()+1); } } function unlockRefund() public { require(block.timestamp > endDate + 7 days, "Too early"); require(!hasCalledVRF, "Already VRFed"); isRefundOpen = true; } function getRefund(uint256[] calldata ids) external nonReentrant { require(block.timestamp > endDate, "Lottery not over"); require(totalSupply() < minTicketsToSell || isRefundOpen, "Enough tickets sold"); uint256 refundAmount = 0; for (uint256 i = 0; i < ids.length; i++) { require(ownerOf(ids[i]) == msg.sender, "Not owner"); _burn(ids[i]); refundAmount = refundAmount.add(ticketPrice); } (bool sent, bytes memory data) = msg.sender.call{value: refundAmount}(""); require(sent, "Transfer failed"); } function refundOwnerAssets() public onlyOwner { require(block.timestamp > endDate, "Lottery not over"); require(totalSupply() < minTicketsToSell || isRefundOpen, "Enough tickets sold"); LINK.safeTransfer(owner(), REFERENCE.LINK_FEE()); IERC721Enumerable(prizeAddress).safeTransferFrom(address(this), owner(), prizeId); } function distributePrize() public onlyOwner { require(totalSupply() >= minTicketsToSell, "Not enough tickets sold"); require(block.timestamp > endDate, "Lottery not over"); require(! hasCalledVRF, "Already called VRF"); LINK.approve(address(RNG_DISTRIBUTOR), REFERENCE.LINK_FEE()); IERC721Enumerable(prizeAddress).setApprovalForAll(address(RNG_DISTRIBUTOR), true); RNG_DISTRIBUTOR.distributeToNftHolders(REFERENCE.LINK_FEE(), address(this), 1, totalSupply(), prizeAddress, prizeId); hasCalledVRF = true; } function claimETH() public onlyOwner { require(hasCalledVRF, "Must call VRF first"); require(IERC721Enumerable(prizeAddress).ownerOf(prizeId) != address(RNG_DISTRIBUTOR), "No VRF yet"); owner().call{value: address(this).balance}(""); } function tokenURI(uint256 id) public view override returns (string memory) { return ITokenURI(REFERENCE.masterTokenURI()).tokenURI(id); } }
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A token is a representation of an on-chain or off-chain asset. The token page shows information such as price, total supply, holders, transfers and social links. Learn more about this page in our Knowledge Base.