Contract Name:
OIRContestManualv2
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.14;
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
contract OIRContestManualv2 is Ownable, ReentrancyGuard {
using Strings for uint256;
using SafeERC20 for IERC20;
mapping(address => bool) public proxyToApproved; // proxy allowance for interaction with future contract
address public treasuryAddress;
struct Contest {
uint16 id; // unique ID for this contest
uint16 entryCount; // number of entries
uint16 maxEntries; // max number of entries
uint16 maxEntriesForThree; // precalculated value for inexpensive comparison
uint16 winningEntry; // winning entry number
address paymentToken; // payment token address; for native, use 0x0000000000000000000000000000000000000000
uint256 price; // price in token
uint256 priceForThree; // precalculated price for three
uint256 payments; // total of payments
uint256 paymentsDistributed; // profit distributed
bool isWon; // if contest has been won
bool isActive; // if contest is accepting entries
bool refunded; // if contest was closed early and refunded
mapping(uint256 => Entry) Entries; // list of entries
mapping(address => uint256) UserEntryCount; // entries count by address
}
mapping(uint256 => address) public ContestWinner; // map contest id to winning address
struct Entry {
address user; // user address
uint256 amount; // amount paid by user
}
uint256 public paymentsWithdrawn;
struct FeeRecipient {
address recipient;
uint256 basisPoints;
}
mapping(uint256 => FeeRecipient) public FeeRecipients;
uint256 public feeRecipientCount;
uint256 public totalFeeBasisPoints;
mapping(uint256 => Contest) public Contests;
uint16 public contestCount;
constructor(address treasury_) {
treasuryAddress = treasury_;
}
// ** - CORE - ** //
function buyOne(uint256 contestID) external payable {
Contest storage contest = Contests[contestID];
require(contest.isActive && ContestWinner[contestID] == address(0), "NOT_ACTIVE");
require(contest.maxEntries > contest.entryCount, "EXCEEDS_MAX_ENTRIES");
if (contest.paymentToken == address(0)) {
require(msg.value == contest.price, "INCORRECT_PAYMENT");
} else {
IERC20(contest.paymentToken).transferFrom(_msgSender(), address(this), contest.price);
}
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: contest.price});
contest.entryCount++;
contest.payments += contest.price;
contest.UserEntryCount[_msgSender()]++;
contest.isActive = contest.entryCount < contest.maxEntries;
emit BuyOne(_msgSender(), contestID, contest.price);
}
function buyThree(uint256 contestID) external payable {
Contest storage contest = Contests[contestID];
require(contest.isActive && ContestWinner[contestID] == address(0), "NOT_ACTIVE");
require(contest.entryCount < contest.maxEntriesForThree, "EXCEEDS_MAX_ENTRIES");
if (contest.paymentToken == address(0)) {
// native
require(msg.value == contest.priceForThree, "INCORRECT_PAYMENT");
} else {
IERC20(contest.paymentToken).transferFrom(_msgSender(), address(this), contest.priceForThree);
}
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: contest.price});
contest.entryCount++;
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: contest.price});
contest.entryCount++;
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: contest.price});
contest.entryCount++;
contest.payments += contest.priceForThree;
contest.UserEntryCount[_msgSender()] += 3;
contest.isActive = contest.entryCount < contest.maxEntries;
emit BuyThree(_msgSender(), contestID, contest.priceForThree);
}
function buy(uint256 contestID, uint256 amount) external payable {
Contest storage contest = Contests[contestID];
require(contest.isActive && ContestWinner[contestID] == address(0), "NOT_ACTIVE");
require(contest.entryCount + amount <= contest.maxEntries, "EXCEEDS_MAX_ENTRIES");
uint256 price = contest.price * amount;
if (contest.paymentToken == address(0)) {
// native
require(msg.value == price, "INCORRECT_PAYMENT");
} else {
IERC20(contest.paymentToken).transferFrom(_msgSender(), address(this), price);
}
for(uint256 x; x < amount; x++) {
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: contest.price});
contest.entryCount++;
}
contest.payments += price;
contest.UserEntryCount[_msgSender()] += amount;
contest.isActive = contest.entryCount < contest.maxEntries;
emit Buy(_msgSender(), contestID, amount, msg.value);
}
function getContestEntries(uint256 contestID) external view returns(Entry[] memory) {
Contest storage contest = Contests[contestID];
Entry[] memory result = new Entry[](contest.entryCount);
for(uint256 x; x < contest.entryCount; x++) {
result[x] = contest.Entries[x];
}
return result;
}
function getUserEntryCount(uint256 contestID, address user) external view returns(uint256) {
return Contests[contestID].UserEntryCount[user];
}
function getUserEntries(uint256 contestID, address user) external view returns(Entry[] memory) {
Contest storage contest = Contests[contestID];
Entry[] memory result = new Entry[](Contests[contestID].UserEntryCount[user]);
uint256 entryCount;
for(uint256 x; x < contest.entryCount; x++) {
if (contest.Entries[x].user == user) {
result[entryCount] = contest.Entries[x];
entryCount++;
}
}
return result;
}
// ** - ADD/EDIT CONTEST - ** //
function addContest(uint16 maxEntries, bool isActive, address paymentToken, uint256 price) external onlyApproved
{
Contest storage contest = Contests[contestCount];
contest.id = contestCount;
contest.maxEntries = maxEntries;
contest.maxEntriesForThree = maxEntries - 2;
contest.isActive = isActive;
contest.paymentToken = paymentToken;
contest.price = price;
contest.priceForThree = price * 3;
emit AddContest(_msgSender(), contestCount);
contestCount++;
}
function cloneContest(uint256 contestID, bool setActive) external onlyApproved
{
Contest storage oldContest = Contests[contestID];
Contest storage newContest = Contests[contestCount];
newContest.id = contestCount;
newContest.maxEntries = oldContest.maxEntries;
newContest.maxEntriesForThree = oldContest.maxEntriesForThree;
newContest.isActive = setActive;
newContest.paymentToken = oldContest.paymentToken;
newContest.price = oldContest.price;
newContest.priceForThree = oldContest.priceForThree;
emit CloneContest(_msgSender(), contestID, contestCount);
contestCount++;
}
function editContest(uint256 contestID, uint16 maxEntries, bool isActive, address paymentToken, uint256 price) external onlyApproved {
require(Contests[contestID].entryCount == 0, "ENTRIES_EXIST");
Contest storage contest = Contests[contestID];
contest.maxEntries = maxEntries;
contest.isActive = isActive;
contest.paymentToken = paymentToken;
contest.price = price;
contest.priceForThree = price * 3;
emit EditContest(_msgSender(), contestCount);
}
function setContestActive(uint256 contestID, bool isActive) external onlyApproved {
require(!isActive || !Contests[contestID].isWon, "ALREADY_WON");
Contests[contestID].isActive = isActive;
emit SetContestActive(_msgSender(), contestID, isActive);
}
function setPriceForContest(uint256 contestID, uint256 price) external onlyApproved {
Contests[contestID].price = price;
Contests[contestID].priceForThree = price * 3;
}
// ** - PROXY - ** //
function singleEntry(uint256 contestID, address receiver) external onlyApproved {
Contest storage contest = Contests[contestID];
require(contest.isActive && ContestWinner[contestID] == address(0), "NOT_ACTIVE");
require(contest.maxEntries > contest.entryCount, "EXCEEDS_MAX_ENTRIES");
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: 0});
contest.entryCount++;
contest.UserEntryCount[receiver]++;
contest.isActive = contest.entryCount < contest.maxEntries;
emit SingleEntry(_msgSender(), receiver, contestID);
}
function tripleEntry(uint256 contestID, address receiver) external onlyApproved {
Contest storage contest = Contests[contestID];
require(contest.isActive && ContestWinner[contestID] == address(0), "NOT_ACTIVE");
require(contest.maxEntriesForThree > contest.entryCount, "EXCEEDS_MAX_ENTRIES");
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: 0});
contest.entryCount++;
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: 0});
contest.entryCount++;
contest.Entries[contest.entryCount] = Entry({user: _msgSender(), amount: 0});
contest.entryCount++;
contest.UserEntryCount[receiver] += 3;
contest.isActive = contest.entryCount < contest.maxEntries;
emit TripleEntry(_msgSender(), receiver, contestID);
}
// ** - ADMIN - ** //
function endContestWithWinner(uint256 contestID, uint16 entryNum) external nonReentrant onlyOwner {
require(ContestWinner[contestID] == address(0), "WINNER_PICKED");
Contest storage contest = Contests[contestID];
require(entryNum < contest.entryCount, "ENTRYNUM>ENTRYCOUNT");
contest.isActive = false;
contest.isWon = true;
contest.winningEntry = entryNum;
ContestWinner[contestID] = contest.Entries[entryNum].user;
emit ManualCompleteContest(_msgSender(), contestID, ContestWinner[contestID]);
}
function endContestWithoutWinner(uint256 contestID) external nonReentrant onlyApproved {
Contest storage contest = Contests[contestID];
require(!contest.isWon, "CONTEST_WON");
require(!contest.refunded, "ALREADY_REFUNDED");
contest.isActive = false;
contest.refunded = true;
//refund entrants
for(uint256 x; x < contest.entryCount; x++) {
Entry storage entry = contest.Entries[x];
if (entry.amount == 0) continue; //don't refund free entries
uint256 amount = entry.amount;
entry.amount == 0;
if (contest.paymentToken == address(0)) {
require(amount <= address(this).balance, "INSUFFICIENT_BNB");
(bool sent, ) = entry.user.call{value: amount}("");
require(sent, "FAILED_SENDING_FUNDS");
} else {
require(amount <= IERC20(contest.paymentToken).balanceOf(address(this)), "INSUFFICIENT_BALANCE");
IERC20(contest.paymentToken).transfer(entry.user, amount);
}
}
emit EndContestWithoutWinner(_msgSender(), contestID);
}
function withdrawBNB() external nonReentrant onlyApproved {
require(treasuryAddress != address(0), "TREASURY_NOT_SET");
uint256 bal = address(this).balance;
(bool sent, ) = treasuryAddress.call{value: bal}("");
require(sent, "FAILED_SENDING_FUNDS");
emit WithdrawBNB(_msgSender(), bal);
}
function withdrawTokens(address _token) external nonReentrant onlyApproved {
require(treasuryAddress != address(0), "TREASURY_NOT_SET");
IERC20(_token).safeTransfer(
treasuryAddress,
IERC20(_token).balanceOf(address(this))
);
}
function flipProxyState(address proxyAddress) public onlyOwner {
proxyToApproved[proxyAddress] = !proxyToApproved[proxyAddress];
}
function isProxyToApproved(address proxyAddress) external view onlyOwner returns(bool) {
return proxyToApproved[proxyAddress];
}
// ** - SETTERS - ** //
function setTreasuryAddress(address addr) external onlyOwner {
treasuryAddress = addr;
}
modifier onlyProxy() {
require(proxyToApproved[_msgSender()] == true, "onlyProxy");
_;
}
modifier onlyApproved() {
require(proxyToApproved[_msgSender()] == true || _msgSender() == owner(), "onlyProxy");
_;
}
event ManualCompleteContest(address indexed user, uint256 indexed contestID, address indexed winner);
event BuyOne(address indexed user, uint256 indexed contestID, uint256 indexed amount);
event BuyThree(address indexed user, uint256 indexed contestID, uint256 indexed amount);
event Buy(address indexed user, uint256 indexed contestID, uint256 indexed amount, uint256 value);
event AddContest(address indexed user, uint256 indexed id);
event EditContest(address indexed user, uint256 indexed id);
event SetContestActive(address indexed user, uint256 indexed id, bool indexed isActive);
event SetPriceForContest(address indexed user, uint256 indexed contestID, uint256 indexed price);
event SingleEntry(address indexed user, address indexed recipient, uint256 contestID);
event TripleEntry(address indexed user, address indexed recipient, uint256 contestID);
event DistributeFunds(address indexed sender, uint256 indexed contestID, address indexed recipient, uint256 amount);
event WithdrawBNB(address indexed sender, uint256 indexed balance);
event EndContestWithWinner(address indexed user, uint256 indexed contestID);
event EndContestWithoutWinner(address indexed user, uint256 indexed contestID);
event CloneContest(address indexed user, uint256 indexed oldContestID, uint256 indexed newContestID);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
pragma solidity ^0.8.0;
/**
* @dev String operations.
*/
library Strings {
bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/
function toString(uint256 value) internal pure returns (string memory) {
// Inspired by OraclizeAPI's implementation - MIT licence
// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
if (value == 0) {
return "0";
}
uint256 temp = value;
uint256 digits;
while (temp != 0) {
digits++;
temp /= 10;
}
bytes memory buffer = new bytes(digits);
while (value != 0) {
digits -= 1;
buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
value /= 10;
}
return string(buffer);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/
function toHexString(uint256 value) internal pure returns (string memory) {
if (value == 0) {
return "0x00";
}
uint256 temp = value;
uint256 length = 0;
while (temp != 0) {
length++;
temp >>= 8;
}
return toHexString(value, length);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
*/
function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
bytes memory buffer = new bytes(2 * length + 2);
buffer[0] = "0";
buffer[1] = "x";
for (uint256 i = 2 * length + 1; i > 1; --i) {
buffer[i] = _HEX_SYMBOLS[value & 0xf];
value >>= 4;
}
require(value == 0, "Strings: hex length insufficient");
return string(buffer);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @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() {
_transferOwnership(_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 {
_transferOwnership(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");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
pragma solidity ^0.8.0;
/**
* @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].
*/
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;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
* @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));
}
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'
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) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_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
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^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 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;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @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 `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 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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @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
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 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");
(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");
(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");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(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);
}
}
}
}