Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.21;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
import "./IXShop.sol";
/// @title Shop Bot Staking Contract
/// @notice This contract allow users to stake SHOP tokens and earn rewards from the fees generated by the platform
contract XShop is IXShop, ERC20("Staked Shop Bot", "xSHOP"), Ownable, ReentrancyGuard {
IERC20 public constant shopToken = IERC20(0x99e186E8671DB8B10d45B7A1C430952a9FBE0D40);
IUniswapV2Router02 public constant uniswapRouter = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
uint256 public constant epochDuration = 1 days;
uint256 public minimumStake = 20000 * 1e18;
// Staking time lock, 5 days by default
uint256 public timeLock = 5 days;
// Total rewards injected
uint256 public totalRewards;
// Snapshot of the epoch, generated by the snapshot(), used to calculate rewards
struct EpochInfo {
// Snapshot time
uint256 timestamp;
// Rewards injected
uint256 rewards;
// Total deposited snap
uint256 supply;
// $SHOP swapped for rewards for re-investors
uint256 shop;
// This is used for aligning with the user deposits/withdrawals during epoch to adjust totalsupply
uint256 deposited;
uint256 withdrawn;
}
uint256 public currentEpoch;
mapping(uint256 => EpochInfo) public epochInfo;
// User info, there's also a balance of xSHOP on the ERC20 super contract
struct UserInfo {
//epoch => total amount deposited during the epoch
mapping(uint256 => uint256) depositedInEpoch;
mapping(uint256 => uint256) withdrawnInEpoch;
mapping(uint256 => bool) isReinvestingOnForEpoch;
// a starting epoch for reward calculation for user - either last claimed or first deposit
uint256 lastEpochClaimedOrReinvested;
uint256 firstDeposit;
}
mapping(address => UserInfo) public userInfo;
// That's for enumerating re-investors because we have to iterate over them to buy SHOP for rewards generated
uint256 public reInvestorsCount;
mapping(address => uint256) public reInvestorsIndex;
mapping(uint256 => address) public reInvestors;
// ========== Configuration ==========
constructor() ReentrancyGuard() {
}
function setMinimumStake(uint256 _minimumStake) public onlyOwner {
minimumStake = _minimumStake;
}
function setTimeLock(uint256 _timeLock) public onlyOwner {
timeLock = _timeLock;
}
// ========== State changing ==========
function deposit(uint256 _amount) public nonReentrant {
require(_amount + balanceOf(msg.sender) >= minimumStake, "Minimum deposit is 20K $SHOP");
require(shopToken.transferFrom(msg.sender, address(this), _amount), "Transfer failed");
if (userInfo[msg.sender].firstDeposit == 0) {
userInfo[msg.sender].firstDeposit = block.timestamp;
}
_updateStake(msg.sender, _amount, true);
emit Deposited(msg.sender, _amount);
}
function withdraw(uint256 _amount) public nonReentrant {
require(balanceOf(msg.sender) >= _amount, "Insufficient balance");
require(userInfo[msg.sender].firstDeposit + timeLock < block.timestamp, "Too early to withdraw");
_updateStake(msg.sender, _amount, false);
require(shopToken.transfer(msg.sender, _amount), "Transfer failed");
emit Withdrawn(msg.sender, _amount);
}
function claimReward() public nonReentrant {
require(currentEpoch > 1, "No rewards have been distributed yet");
// uint256 lastSnapshotTime = epochInfo[currentEpoch - 1].timestamp;
// require(lastSnapshotTime + epochDuration <= block.timestamp, "Too early to calculate rewards");
require (!(reInvestorsIndex[msg.sender] > 0), "Auto-compounding is enabled");
uint256 reward = calculateRewardForUser(msg.sender);
require(reward > 0, "No reward available");
require(address(this).balance >= reward, "Insufficient contract balance to transfer reward");
payable(msg.sender).transfer(reward);
userInfo[msg.sender].lastEpochClaimedOrReinvested = currentEpoch - 1;
emit Claimed(msg.sender, reward);
}
// we need it to be only owner to keep epochs precise
function snapshot() public payable nonReentrant onlyOwner {
require(msg.value > 0, "ETH amount must be greater than 0");
uint256 lastSnapshotTime = 0;
if (currentEpoch > 0) {
lastSnapshotTime = epochInfo[currentEpoch - 1].timestamp;
require(block.timestamp >= lastSnapshotTime + epochDuration - 5 minutes, "Too early for a new snapshot");
}
totalRewards += msg.value;
epochInfo[currentEpoch].rewards = msg.value;
epochInfo[currentEpoch].timestamp = block.timestamp;
epochInfo[currentEpoch].supply = totalSupply();
// swap ETH for autocompounding
uint256 ethToSell = 0;
uint256[] memory stakersRewarsInEpoch = new uint256[](reInvestorsCount + 1);
for (uint256 i = 1; i <= reInvestorsCount; i++) {
address user = reInvestors[i];
userInfo[user].isReinvestingOnForEpoch[currentEpoch] = true;
stakersRewarsInEpoch[i] = _calculateReward(user, true);
ethToSell += stakersRewarsInEpoch[i];
if (ethToSell > 0) {
userInfo[user].lastEpochClaimedOrReinvested = currentEpoch;
}
}
uint256 xShopToMintTotal = 0;
if (ethToSell > 0) {
xShopToMintTotal = _swapEthForShop(ethToSell);
epochInfo[currentEpoch].shop = xShopToMintTotal;
//now updating staking balances
for (uint256 i = 1; i <= reInvestorsCount; i++) {
uint256 xShopToMint = stakersRewarsInEpoch[i] * xShopToMintTotal / ethToSell;
_updateStake(msg.sender, xShopToMint, true);
}
}
emit Snapshot(currentEpoch, msg.value, msg.sender);
currentEpoch++;
}
function toggleReinvesting() public {
bool currentStatus = reInvestorsIndex[msg.sender] > 0;
if (!currentStatus) {
// Add re-investor to the renumeration
if (reInvestorsIndex[msg.sender] == 0) {
reInvestorsCount++;
reInvestorsIndex[msg.sender] = reInvestorsCount;
reInvestors[reInvestorsCount] = msg.sender;
userInfo[msg.sender].isReinvestingOnForEpoch[currentEpoch] = true;
}
}
else {
// Remove re-investor from the renumeration
if (reInvestorsIndex[msg.sender] != 0) {
uint256 index = reInvestorsIndex[msg.sender];
address lastReinvestor = reInvestors[reInvestorsCount];
// Swap the msg.sender to remove with the last msg.sender
reInvestors[index] = lastReinvestor;
reInvestorsIndex[lastReinvestor] = index;
// Remove the last msg.sender and update count
delete reInvestors[reInvestorsCount];
delete reInvestorsIndex[msg.sender];
reInvestorsCount--;
userInfo[msg.sender].isReinvestingOnForEpoch[currentEpoch] = false;
}
}
emit Reinvestment(msg.sender, !currentStatus);
}
function rescueETH(uint256 _weiAmount) external {
payable(owner()).transfer(_weiAmount);
}
function rescueERC20(address _tokenAdd, uint256 _amount) external {
IERC20(_tokenAdd).transfer(owner(), _amount);
}
// ========== View functions ==========
function getPendingReward() public view returns (uint256) {
return calculateRewardForUser(msg.sender);
}
function calculateRewardForUser(address user) public view returns (uint256) {
return _calculateReward(user, false);
}
function isReinvesting(address user) external view returns (bool) {
return reInvestorsIndex[user] > 0;
}
// ========== Internal functions ==========
function _updateStake(address _user, uint256 _amount, bool _isDeposit) internal {
if (_isDeposit) {
userInfo[_user].depositedInEpoch[currentEpoch] += _amount;
epochInfo[currentEpoch].deposited += _amount;
_mint(_user, _amount);
} else {
userInfo[_user].withdrawnInEpoch[currentEpoch] += _amount;
epochInfo[currentEpoch].withdrawn += _amount;
_burn(_user, _amount);
}
}
function _swapEthForShop(uint256 _ethAmount) internal returns (uint256) {
address[] memory path = new address[](2);
path[0] = uniswapRouter.WETH();
path[1] = address(shopToken);
// 15 seeconds from the current block time
uint256 deadline = block.timestamp + 15;
// Swap and return the amount of SHOP tokens received
uint[] memory amounts = uniswapRouter.swapExactETHForTokens{value: _ethAmount}(
0, // Accept any amount of SHOP
path,
address(this),
deadline
);
emit Swapped(_ethAmount, amounts[1]);
// Return the amount of SHOP tokens received
return amounts[1];
}
// Mock function for demonstration purposes. In reality, you'd interact with a decentralized exchange contract here.
function _calculateReward(address _user, bool _isForReinvestment) internal view returns (uint256) {
uint256 reward = 0;
if (currentEpoch < 1) {
return 0;
}
uint256 userBalanceInEpoch = balanceOf(_user);
uint256 i = currentEpoch;
while (i >= userInfo[_user].lastEpochClaimedOrReinvested && i <= currentEpoch) {
uint256 supplyInEpoch = epochInfo[i].supply;
uint256 epochReward = supplyInEpoch == 0 || i >= currentEpoch - 1 ? 0 :
userBalanceInEpoch * epochInfo[i].rewards / supplyInEpoch;
if (epochReward > 0 &&
(_isForReinvestment && reInvestorsIndex[_user] > 0 ||
!_isForReinvestment && !userInfo[_user].isReinvestingOnForEpoch[i])) {
reward += epochReward;
}
if (i == 0) {
break;
}
userBalanceInEpoch -= userInfo[_user].depositedInEpoch[i];
userBalanceInEpoch += userInfo[_user].withdrawnInEpoch[i];
i--;
}
return reward;
}
function _beforeTokenTransfer(address _from, address _to, uint256 _amount) internal override {
super._beforeTokenTransfer(_from, _to, _amount);
require(_from == address(0) || _to == address(0), "Only stake or unstake");
}
receive() external payable {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.21;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
interface IXShop is IERC20 {
event Snapshot(uint256 epoch, uint256 rewards, address indexed from);
event Swapped(uint256 eth, uint256 shop);
event Deposited(address indexed user, uint256 amount);
event Withdrawn(address indexed user, uint256 amount);
event Claimed(address indexed user, uint256 reward);
event Reinvestment(address indexed user, bool status);
// ========== State Changing Functions ==========
// Deposit (stake) SHOP tokens and get XSHOP tokens of the same amount in return
function deposit(uint256 _amount) external;
// Withdraw (unstake) SHOP tokens and get XSHOP tokens back
function withdraw(uint256 _amount) external;
// Claim pending reward
function claimReward() external;
// Snapshot the current epoch and distribute rewards (ETH sent in msg.value)
function snapshot() external payable;
// Switch Autocompounding on/off
function toggleReinvesting() external;
// Get ETH from the contract
function rescueETH(uint256 _weiAmount) external;
// Get ERC20 from the contract
function rescueERC20(address _tokenAdd, uint256 _amount) external;
// ========== View functions ==========
// Get pending rewards
function calculateRewardForUser(address user) external view returns (uint256);
// Get auto-compounding status
function isReinvesting(address user) external view returns (bool);
// Total rewards injected, - this is only for distribution
function totalRewards() external view returns (uint256);
// Current epoch ordinal number, starts from 0 and increases by 1 after each snapshot (by default every 24 hours)
function currentEpoch() external view returns (uint256);
}
pragma solidity >=0.6.2;
import './IUniswapV2Router01.sol';
interface IUniswapV2Router02 is IUniswapV2Router01 {
function removeLiquidityETHSupportingFeeOnTransferTokens(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external returns (uint amountETH);
function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external returns (uint amountETH);
function swapExactTokensForTokensSupportingFeeOnTransferTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external;
function swapExactETHForTokensSupportingFeeOnTransferTokens(
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external payable;
function swapExactTokensForETHSupportingFeeOnTransferTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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() {
_nonReentrantBefore();
_;
_nonReentrantAfter();
}
function _nonReentrantBefore() private {
// On the first call to nonReentrant, _status will be _NOT_ENTERED
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
}
function _nonReentrantAfter() private {
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
/**
* @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
* `nonReentrant` function in the call stack.
*/
function _reentrancyGuardEntered() internal view returns (bool) {
return _status == _ENTERED;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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 Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
_checkOwner();
_;
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if the sender is not the owner.
*/
function _checkOwner() internal view virtual {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby disabling 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 (last updated v4.9.0) (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* The default value of {decimals} is 18. To change this, you should override
* this function so it returns a different value.
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead returning `false` on failure. This behavior is nonetheless
* conventional and does not conflict with the expectations of ERC20
* applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the default value returned by this function, unless
* it's overridden.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
* `transferFrom`. This is semantically equivalent to an infinite approval.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, spender) + addedValue);
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `from` to `to`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
function _transfer(address from, address to, uint256 amount) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
// Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
// decrementing then incrementing.
_balances[to] += amount;
}
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply += amount;
unchecked {
// Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
_balances[account] += amount;
}
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
// Overflow not possible: amount <= accountBalance <= totalSupply.
_totalSupply -= amount;
}
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Updates `owner` s allowance for `spender` based on spent `amount`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @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);
}
pragma solidity >=0.6.2;
interface IUniswapV2Router01 {
function factory() external pure returns (address);
function WETH() external pure returns (address);
function addLiquidity(
address tokenA,
address tokenB,
uint amountADesired,
uint amountBDesired,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) external returns (uint amountA, uint amountB, uint liquidity);
function addLiquidityETH(
address token,
uint amountTokenDesired,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external payable returns (uint amountToken, uint amountETH, uint liquidity);
function removeLiquidity(
address tokenA,
address tokenB,
uint liquidity,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) external returns (uint amountA, uint amountB);
function removeLiquidityETH(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external returns (uint amountToken, uint amountETH);
function removeLiquidityWithPermit(
address tokenA,
address tokenB,
uint liquidity,
uint amountAMin,
uint amountBMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external returns (uint amountA, uint amountB);
function removeLiquidityETHWithPermit(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external returns (uint amountToken, uint amountETH);
function swapExactTokensForTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
function swapTokensForExactTokens(
uint amountOut,
uint amountInMax,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
external
payable
returns (uint[] memory amounts);
function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
external
returns (uint[] memory amounts);
function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
external
returns (uint[] memory amounts);
function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
external
payable
returns (uint[] memory amounts);
function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}
// 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 v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}