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September 15, 2023 17:30
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// SPDX-License-Identifier: MIT | |
pragma solidity ^0.8.2; | |
/** | |
* @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 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 Context { | |
function _msgSender() internal view virtual returns (address) { | |
return msg.sender; | |
} | |
} | |
/** | |
* @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 Ownable is Context { | |
address private _owner; | |
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); | |
/** | |
* @dev Initializes the contract setting the deployer as the initial owner. | |
*/ | |
constructor() { | |
_setOwner(_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() external virtual onlyOwner { | |
_setOwner(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"); | |
_setOwner(newOwner); | |
} | |
function _setOwner(address newOwner) private { | |
address oldOwner = _owner; | |
_owner = newOwner; | |
emit OwnershipTransferred(oldOwner, newOwner); | |
} | |
} | |
/** | |
* @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]. | |
*/ | |
abstract 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() { | |
_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 making 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; | |
} | |
} | |
/** | |
* @dev Interface of the ERC20 standard as defined in the EIP. | |
*/ | |
interface IERC20 { | |
/** | |
* @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); | |
/** | |
* @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 `to`. | |
* | |
* Returns a boolean value indicating whether the operation succeeded. | |
* | |
* Emits a {Transfer} event. | |
*/ | |
function transfer(address to, 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 `from` to `to` 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 from, address to, uint256 amount) external returns (bool); | |
} | |
/** | |
* @dev Required interface of an ERC721 compliant contract. | |
*/ | |
interface IERC721 { | |
/** | |
* @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`. | |
* | |
* 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 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 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 Required interface of an ERC1155 compliant contract, as defined in the | |
* https://eips.ethereum.org/EIPS/eip-1155[EIP]. | |
*/ | |
interface IERC1155 { | |
/** | |
* @dev Returns the value of tokens of token type `id` owned by `account`. | |
* | |
* Requirements: | |
* | |
* - `account` cannot be the zero address. | |
*/ | |
function balanceOf(address account, uint256 id) external view returns (uint256); | |
/** | |
* @dev Transfers a `value` amount of tokens of type `id` from `from` to `to`. | |
* | |
* WARNING: This function can potentially allow a reentrancy attack when transferring tokens | |
* to an untrusted contract, when invoking {onERC1155Received} on the receiver. | |
* Ensure to follow the checks-effects-interactions pattern and consider employing | |
* reentrancy guards when interacting with untrusted contracts. | |
* | |
* Emits a {TransferSingle} event. | |
* | |
* Requirements: | |
* | |
* - `to` cannot be the zero address. | |
* - If the caller is not `from`, it must have been approved to spend ``from``'s tokens via {setApprovalForAll}. | |
* - `from` must have a balance of tokens of type `id` of at least `value` amount. | |
* - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the | |
* acceptance magic value. | |
*/ | |
function safeTransferFrom(address from, address to, uint256 id, uint256 value, bytes calldata data) external; | |
} | |
/** | |
* @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; | |
assembly { | |
size := extcodesize(account) | |
} | |
return size > 0; | |
} | |
/** | |
* @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-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"); | |
(bool success, bytes memory returndata) = target.call{value: value}(data); | |
return verifyCallResult(success, returndata, errorMessage); | |
} | |
/** | |
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the | |
* revert reason using the provided one. | |
* | |
* _Available since v4.3._ | |
*/ | |
function verifyCallResult( | |
bool success, | |
bytes memory returndata, | |
string memory errorMessage | |
) internal 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 | |
assembly { | |
let returndata_size := mload(returndata) | |
revert(add(32, returndata), returndata_size) | |
} | |
} else { | |
revert(errorMessage); | |
} | |
} | |
} | |
} | |
/** | |
* @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 Address for address; | |
function safeTransfer( | |
IERC20 token, | |
address to, | |
uint256 value | |
) internal { | |
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value)); | |
} | |
/** | |
* @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the | |
* calling contract. If `token` returns no value, non-reverting calls are assumed to be successful. | |
*/ | |
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal { | |
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value)); | |
} | |
/** | |
* @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"); | |
require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed"); | |
} | |
} |
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