Contract Name:
UniswapV2_ZapIn_General_V5
Contract Source Code:
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// Copyright (C) 2021 zapper
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
///@author Zapper
///@notice This contract adds liquidity to Uniswap V2 pools using ETH or any ERC20 Token.
// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;
import "../_base/ZapInBaseV3.sol";
// import "@uniswap/lib/contracts/libraries/Babylonian.sol";
library Babylonian {
function sqrt(uint256 y) internal pure returns (uint256 z) {
if (y > 3) {
z = y;
uint256 x = y / 2 + 1;
while (x < z) {
z = x;
x = (y / x + x) / 2;
}
} else if (y != 0) {
z = 1;
}
// else z = 0
}
}
interface IWETH {
function deposit() external payable;
function transfer(address to, uint256 value) external returns (bool);
function withdraw(uint256) external;
}
interface IUniswapV2Factory {
function getPair(address tokenA, address tokenB)
external
view
returns (address);
}
interface IUniswapV2Router02 {
function factory() external pure returns (address);
function WETH() external pure returns (address);
function addLiquidity(
address tokenA,
address tokenB,
uint256 amountADesired,
uint256 amountBDesired,
uint256 amountAMin,
uint256 amountBMin,
address to,
uint256 deadline
)
external
returns (
uint256 amountA,
uint256 amountB,
uint256 liquidity
);
function addLiquidityETH(
address token,
uint256 amountTokenDesired,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline
)
external
payable
returns (
uint256 amountToken,
uint256 amountETH,
uint256 liquidity
);
function removeLiquidity(
address tokenA,
address tokenB,
uint256 liquidity,
uint256 amountAMin,
uint256 amountBMin,
address to,
uint256 deadline
) external returns (uint256 amountA, uint256 amountB);
function removeLiquidityETH(
address token,
uint256 liquidity,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline
) external returns (uint256 amountToken, uint256 amountETH);
function removeLiquidityWithPermit(
address tokenA,
address tokenB,
uint256 liquidity,
uint256 amountAMin,
uint256 amountBMin,
address to,
uint256 deadline,
bool approveMax,
uint8 v,
bytes32 r,
bytes32 s
) external returns (uint256 amountA, uint256 amountB);
function removeLiquidityETHWithPermit(
address token,
uint256 liquidity,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline,
bool approveMax,
uint8 v,
bytes32 r,
bytes32 s
) external returns (uint256 amountToken, uint256 amountETH);
function swapExactTokensForTokens(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external returns (uint256[] memory amounts);
function swapTokensForExactTokens(
uint256 amountOut,
uint256 amountInMax,
address[] calldata path,
address to,
uint256 deadline
) external returns (uint256[] memory amounts);
function swapExactETHForTokens(
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external payable returns (uint256[] memory amounts);
function swapTokensForExactETH(
uint256 amountOut,
uint256 amountInMax,
address[] calldata path,
address to,
uint256 deadline
) external returns (uint256[] memory amounts);
function swapExactTokensForETH(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external returns (uint256[] memory amounts);
function swapETHForExactTokens(
uint256 amountOut,
address[] calldata path,
address to,
uint256 deadline
) external payable returns (uint256[] memory amounts);
function removeLiquidityETHSupportingFeeOnTransferTokens(
address token,
uint256 liquidity,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline
) external returns (uint256 amountETH);
function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
address token,
uint256 liquidity,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline,
bool approveMax,
uint8 v,
bytes32 r,
bytes32 s
) external returns (uint256 amountETH);
function swapExactTokensForTokensSupportingFeeOnTransferTokens(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external;
function swapExactETHForTokensSupportingFeeOnTransferTokens(
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external payable;
function swapExactTokensForETHSupportingFeeOnTransferTokens(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external;
function quote(
uint256 amountA,
uint256 reserveA,
uint256 reserveB
) external pure returns (uint256 amountB);
function getAmountOut(
uint256 amountIn,
uint256 reserveIn,
uint256 reserveOut
) external pure returns (uint256 amountOut);
function getAmountIn(
uint256 amountOut,
uint256 reserveIn,
uint256 reserveOut
) external pure returns (uint256 amountIn);
function getAmountsOut(uint256 amountIn, address[] calldata path)
external
view
returns (uint256[] memory amounts);
function getAmountsIn(uint256 amountOut, address[] calldata path)
external
view
returns (uint256[] memory amounts);
}
interface IUniswapV2Pair {
function token0() external pure returns (address);
function token1() external pure returns (address);
function getReserves()
external
view
returns (
uint112 _reserve0,
uint112 _reserve1,
uint32 _blockTimestampLast
);
}
contract UniswapV2_ZapIn_General_V5 is ZapInBaseV3 {
using SafeERC20 for IERC20;
IUniswapV2Factory private constant UniSwapV2FactoryAddress =
IUniswapV2Factory(0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f);
IUniswapV2Router02 private constant uniswapRouter =
IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
address private constant wethTokenAddress =
0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
uint256 private constant deadline =
0xf000000000000000000000000000000000000000000000000000000000000000;
constructor(uint256 _goodwill, uint256 _affiliateSplit)
ZapBaseV2(_goodwill, _affiliateSplit)
{
// 0x exchange
approvedTargets[0xDef1C0ded9bec7F1a1670819833240f027b25EfF] = true;
}
event zapIn(address sender, address pool, uint256 tokensRec);
/**
@notice This function is used to invest in given Uniswap V2 pair through ETH/ERC20 Tokens
@param _FromTokenContractAddress The ERC20 token used for investment (address(0x00) if ether)
@param _pairAddress The Uniswap pair address
@param _amount The amount of fromToken to invest
@param _minPoolTokens Reverts if less tokens received than this
@param _swapTarget Excecution target for the first swap
@param swapData DEX quote data
@param affiliate Affiliate address
@param transferResidual Set false to save gas by donating the residual remaining after a Zap
@param shouldSellEntireBalance If True transfers entrire allowable amount from another contract
@return Amount of LP bought
*/
function ZapIn(
address _FromTokenContractAddress,
address _pairAddress,
uint256 _amount,
uint256 _minPoolTokens,
address _swapTarget,
bytes calldata swapData,
address affiliate,
bool transferResidual,
bool shouldSellEntireBalance
) external payable stopInEmergency returns (uint256) {
uint256 toInvest =
_pullTokens(
_FromTokenContractAddress,
_amount,
affiliate,
true,
shouldSellEntireBalance
);
uint256 LPBought =
_performZapIn(
_FromTokenContractAddress,
_pairAddress,
toInvest,
_swapTarget,
swapData,
transferResidual
);
require(LPBought >= _minPoolTokens, "High Slippage");
emit zapIn(msg.sender, _pairAddress, LPBought);
IERC20(_pairAddress).safeTransfer(msg.sender, LPBought);
return LPBought;
}
function _getPairTokens(address _pairAddress)
internal
pure
returns (address token0, address token1)
{
IUniswapV2Pair uniPair = IUniswapV2Pair(_pairAddress);
token0 = uniPair.token0();
token1 = uniPair.token1();
}
function _performZapIn(
address _FromTokenContractAddress,
address _pairAddress,
uint256 _amount,
address _swapTarget,
bytes memory swapData,
bool transferResidual
) internal returns (uint256) {
uint256 intermediateAmt;
address intermediateToken;
(address _ToUniswapToken0, address _ToUniswapToken1) =
_getPairTokens(_pairAddress);
if (
_FromTokenContractAddress != _ToUniswapToken0 &&
_FromTokenContractAddress != _ToUniswapToken1
) {
// swap to intermediate
(intermediateAmt, intermediateToken) = _fillQuote(
_FromTokenContractAddress,
_pairAddress,
_amount,
_swapTarget,
swapData
);
} else {
intermediateToken = _FromTokenContractAddress;
intermediateAmt = _amount;
}
// divide intermediate into appropriate amount to add liquidity
(uint256 token0Bought, uint256 token1Bought) =
_swapIntermediate(
intermediateToken,
_ToUniswapToken0,
_ToUniswapToken1,
intermediateAmt
);
return
_uniDeposit(
_ToUniswapToken0,
_ToUniswapToken1,
token0Bought,
token1Bought,
transferResidual
);
}
function _uniDeposit(
address _ToUnipoolToken0,
address _ToUnipoolToken1,
uint256 token0Bought,
uint256 token1Bought,
bool transferResidual
) internal returns (uint256) {
_approveToken(_ToUnipoolToken0, address(uniswapRouter), token0Bought);
_approveToken(_ToUnipoolToken1, address(uniswapRouter), token1Bought);
(uint256 amountA, uint256 amountB, uint256 LP) =
uniswapRouter.addLiquidity(
_ToUnipoolToken0,
_ToUnipoolToken1,
token0Bought,
token1Bought,
1,
1,
address(this),
deadline
);
if (transferResidual) {
//Returning Residue in token0, if any.
if (token0Bought - amountA > 0) {
IERC20(_ToUnipoolToken0).safeTransfer(
msg.sender,
token0Bought - amountA
);
}
//Returning Residue in token1, if any
if (token1Bought - amountB > 0) {
IERC20(_ToUnipoolToken1).safeTransfer(
msg.sender,
token1Bought - amountB
);
}
}
return LP;
}
function _fillQuote(
address _fromTokenAddress,
address _pairAddress,
uint256 _amount,
address _swapTarget,
bytes memory swapData
) internal returns (uint256 amountBought, address intermediateToken) {
if (_swapTarget == wethTokenAddress) {
IWETH(wethTokenAddress).deposit{ value: _amount }();
return (_amount, wethTokenAddress);
}
uint256 valueToSend;
if (_fromTokenAddress == address(0)) {
valueToSend = _amount;
} else {
_approveToken(_fromTokenAddress, _swapTarget, _amount);
}
(address _token0, address _token1) = _getPairTokens(_pairAddress);
IERC20 token0 = IERC20(_token0);
IERC20 token1 = IERC20(_token1);
uint256 initialBalance0 = token0.balanceOf(address(this));
uint256 initialBalance1 = token1.balanceOf(address(this));
require(approvedTargets[_swapTarget], "Target not Authorized");
(bool success, ) = _swapTarget.call{ value: valueToSend }(swapData);
require(success, "Error Swapping Tokens 1");
uint256 finalBalance0 =
token0.balanceOf(address(this)) - initialBalance0;
uint256 finalBalance1 =
token1.balanceOf(address(this)) - initialBalance1;
if (finalBalance0 > finalBalance1) {
amountBought = finalBalance0;
intermediateToken = _token0;
} else {
amountBought = finalBalance1;
intermediateToken = _token1;
}
require(amountBought > 0, "Swapped to Invalid Intermediate");
}
function _swapIntermediate(
address _toContractAddress,
address _ToUnipoolToken0,
address _ToUnipoolToken1,
uint256 _amount
) internal returns (uint256 token0Bought, uint256 token1Bought) {
IUniswapV2Pair pair =
IUniswapV2Pair(
UniSwapV2FactoryAddress.getPair(
_ToUnipoolToken0,
_ToUnipoolToken1
)
);
(uint256 res0, uint256 res1, ) = pair.getReserves();
if (_toContractAddress == _ToUnipoolToken0) {
uint256 amountToSwap = calculateSwapInAmount(res0, _amount);
//if no reserve or a new pair is created
if (amountToSwap <= 0) amountToSwap = _amount / 2;
token1Bought = _token2Token(
_toContractAddress,
_ToUnipoolToken1,
amountToSwap
);
token0Bought = _amount - amountToSwap;
} else {
uint256 amountToSwap = calculateSwapInAmount(res1, _amount);
//if no reserve or a new pair is created
if (amountToSwap <= 0) amountToSwap = _amount / 2;
token0Bought = _token2Token(
_toContractAddress,
_ToUnipoolToken0,
amountToSwap
);
token1Bought = _amount - amountToSwap;
}
}
function calculateSwapInAmount(uint256 reserveIn, uint256 userIn)
internal
pure
returns (uint256)
{
return
(Babylonian.sqrt(
reserveIn * ((userIn * 3988000) + (reserveIn * 3988009))
) - (reserveIn * 1997)) / 1994;
}
/**
@notice This function is used to swap ERC20 <> ERC20
@param _FromTokenContractAddress The token address to swap from.
@param _ToTokenContractAddress The token address to swap to.
@param tokens2Trade The amount of tokens to swap
@return tokenBought The quantity of tokens bought
*/
function _token2Token(
address _FromTokenContractAddress,
address _ToTokenContractAddress,
uint256 tokens2Trade
) internal returns (uint256 tokenBought) {
if (_FromTokenContractAddress == _ToTokenContractAddress) {
return tokens2Trade;
}
_approveToken(
_FromTokenContractAddress,
address(uniswapRouter),
tokens2Trade
);
address pair =
UniSwapV2FactoryAddress.getPair(
_FromTokenContractAddress,
_ToTokenContractAddress
);
require(pair != address(0), "No Swap Available");
address[] memory path = new address[](2);
path[0] = _FromTokenContractAddress;
path[1] = _ToTokenContractAddress;
tokenBought = uniswapRouter.swapExactTokensForTokens(
tokens2Trade,
1,
path,
address(this),
deadline
)[path.length - 1];
require(tokenBought > 0, "Error Swapping Tokens 2");
}
}
// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;
import "../oz/0.8.0/access/Ownable.sol";
import "../oz/0.8.0/token/ERC20/utils/SafeERC20.sol";
abstract contract ZapBaseV2 is Ownable {
using SafeERC20 for IERC20;
bool public stopped = false;
// if true, goodwill is not deducted
mapping(address => bool) public feeWhitelist;
uint256 public goodwill;
// % share of goodwill (0-100 %)
uint256 affiliateSplit;
// restrict affiliates
mapping(address => bool) public affiliates;
// affiliate => token => amount
mapping(address => mapping(address => uint256)) public affiliateBalance;
// token => amount
mapping(address => uint256) public totalAffiliateBalance;
// swapTarget => approval status
mapping(address => bool) public approvedTargets;
address internal constant ETHAddress =
0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
constructor(uint256 _goodwill, uint256 _affiliateSplit) {
goodwill = _goodwill;
affiliateSplit = _affiliateSplit;
}
// circuit breaker modifiers
modifier stopInEmergency {
if (stopped) {
revert("Temporarily Paused");
} else {
_;
}
}
function _getBalance(address token)
internal
view
returns (uint256 balance)
{
if (token == address(0)) {
balance = address(this).balance;
} else {
balance = IERC20(token).balanceOf(address(this));
}
}
function _approveToken(address token, address spender) internal {
IERC20 _token = IERC20(token);
if (_token.allowance(address(this), spender) > 0) return;
else {
_token.safeApprove(spender, type(uint256).max);
}
}
function _approveToken(
address token,
address spender,
uint256 amount
) internal {
IERC20 _token = IERC20(token);
_token.safeApprove(spender, 0);
_token.safeApprove(spender, amount);
}
// - to Pause the contract
function toggleContractActive() public onlyOwner {
stopped = !stopped;
}
function set_feeWhitelist(address zapAddress, bool status)
external
onlyOwner
{
feeWhitelist[zapAddress] = status;
}
function set_new_goodwill(uint256 _new_goodwill) public onlyOwner {
require(
_new_goodwill >= 0 && _new_goodwill <= 100,
"GoodWill Value not allowed"
);
goodwill = _new_goodwill;
}
function set_new_affiliateSplit(uint256 _new_affiliateSplit)
external
onlyOwner
{
require(
_new_affiliateSplit <= 100,
"Affiliate Split Value not allowed"
);
affiliateSplit = _new_affiliateSplit;
}
function set_affiliate(address _affiliate, bool _status)
external
onlyOwner
{
affiliates[_affiliate] = _status;
}
///@notice Withdraw goodwill share, retaining affilliate share
function withdrawTokens(address[] calldata tokens) external onlyOwner {
for (uint256 i = 0; i < tokens.length; i++) {
uint256 qty;
if (tokens[i] == ETHAddress) {
qty = address(this).balance - totalAffiliateBalance[tokens[i]];
Address.sendValue(payable(owner()), qty);
} else {
qty =
IERC20(tokens[i]).balanceOf(address(this)) -
totalAffiliateBalance[tokens[i]];
IERC20(tokens[i]).safeTransfer(owner(), qty);
}
}
}
///@notice Withdraw affilliate share, retaining goodwill share
function affilliateWithdraw(address[] calldata tokens) external {
uint256 tokenBal;
for (uint256 i = 0; i < tokens.length; i++) {
tokenBal = affiliateBalance[msg.sender][tokens[i]];
affiliateBalance[msg.sender][tokens[i]] = 0;
totalAffiliateBalance[tokens[i]] =
totalAffiliateBalance[tokens[i]] -
tokenBal;
if (tokens[i] == ETHAddress) {
Address.sendValue(payable(msg.sender), tokenBal);
} else {
IERC20(tokens[i]).safeTransfer(msg.sender, tokenBal);
}
}
}
function setApprovedTargets(
address[] calldata targets,
bool[] calldata isApproved
) external onlyOwner {
require(targets.length == isApproved.length, "Invalid Input length");
for (uint256 i = 0; i < targets.length; i++) {
approvedTargets[targets[i]] = isApproved[i];
}
}
receive() external payable {
require(msg.sender != tx.origin, "Do not send ETH directly");
}
}
// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;
import "./ZapBaseV2.sol";
abstract contract ZapInBaseV3 is ZapBaseV2 {
using SafeERC20 for IERC20;
function _pullTokens(
address token,
uint256 amount,
address affiliate,
bool enableGoodwill,
bool shouldSellEntireBalance
) internal returns (uint256 value) {
uint256 totalGoodwillPortion;
if (token == address(0)) {
require(msg.value > 0, "No eth sent");
// subtract goodwill
totalGoodwillPortion = _subtractGoodwill(
ETHAddress,
msg.value,
affiliate,
enableGoodwill
);
return msg.value - totalGoodwillPortion;
}
require(amount > 0, "Invalid token amount");
require(msg.value == 0, "Eth sent with token");
//transfer token
if (shouldSellEntireBalance) {
require(
Address.isContract(msg.sender),
"ERR: shouldSellEntireBalance is true for EOA"
);
amount = IERC20(token).allowance(msg.sender, address(this));
}
IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
// subtract goodwill
totalGoodwillPortion = _subtractGoodwill(
token,
amount,
affiliate,
enableGoodwill
);
return amount - totalGoodwillPortion;
}
function _subtractGoodwill(
address token,
uint256 amount,
address affiliate,
bool enableGoodwill
) internal returns (uint256 totalGoodwillPortion) {
bool whitelisted = feeWhitelist[msg.sender];
if (enableGoodwill && !whitelisted && goodwill > 0) {
totalGoodwillPortion = (amount * goodwill) / 10000;
if (affiliates[affiliate]) {
if (token == address(0)) {
token = ETHAddress;
}
uint256 affiliatePortion =
(totalGoodwillPortion * affiliateSplit) / 100;
affiliateBalance[affiliate][token] =
affiliateBalance[affiliate][token] +
affiliatePortion;
totalAffiliateBalance[token] =
totalAffiliateBalance[token] +
affiliatePortion;
}
}
}
}
// SPDX-License-Identifier: MIT
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() {
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;
}
}
// SPDX-License-Identifier: MIT
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 `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
);
}
// SPDX-License-Identifier: MIT
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'
// 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) + 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
// solhint-disable-next-line max-line-length
require(
abi.decode(returndata, (bool)),
"SafeERC20: ERC20 operation did not succeed"
);
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly {
size := extcodesize(account)
}
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(
address(this).balance >= amount,
"Address: insufficient balance"
);
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(
success,
"Address: unable to send value, recipient may have reverted"
);
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data)
internal
returns (bytes memory)
{
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return
functionCallWithValue(
target,
data,
value,
"Address: low-level call with value failed"
);
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(
address(this).balance >= value,
"Address: insufficient balance for call"
);
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) =
target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data)
internal
view
returns (bytes memory)
{
return
functionStaticCall(
target,
data,
"Address: low-level static call failed"
);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data)
internal
returns (bytes memory)
{
return
functionDelegateCall(
target,
data,
"Address: low-level delegate call failed"
);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) private pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
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) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}