// SPDX-License-Identifier: MITpragmasolidity ^0.8.0;/**
* @dev Collection of functions related to the address type
*/libraryAddress{
/**
* @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
* ====
*/functionisContract(address account) internalviewreturns (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-assemblyassembly {
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].
*/functionsendValue(addresspayable 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._
*/functionfunctionCall(address target, bytesmemory data)
internalreturns (bytesmemory)
{
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._
*/functionfunctionCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
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._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value
) internalreturns (bytesmemory) {
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._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value,
stringmemory errorMessage
) internalreturns (bytesmemory) {
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, bytesmemory 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._
*/functionfunctionStaticCall(address target, bytesmemory data)
internalviewreturns (bytesmemory)
{
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._
*/functionfunctionStaticCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalviewreturns (bytesmemory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytesmemory 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._
*/functionfunctionDelegateCall(address target, bytesmemory data)
internalreturns (bytesmemory)
{
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._
*/functionfunctionDelegateCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytesmemory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function_verifyCallResult(bool success,
bytesmemory returndata,
stringmemory errorMessage
) privatepurereturns (bytesmemory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if presentif (returndata.length>0) {
// The easiest way to bubble the revert reason is using memory via assembly// solhint-disable-next-line no-inline-assemblyassembly {
let returndata_size :=mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
Contract Source Code
File 2 of 9: Context.sol
// SPDX-License-Identifier: MITpragmasolidity ^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.
*/abstractcontractContext{
function_msgSender() internalviewvirtualreturns (address) {
returnmsg.sender;
}
function_msgData() internalviewvirtualreturns (bytescalldata) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691returnmsg.data;
}
}
Contract Source Code
File 3 of 9: Curve_ZapIn_General_V4.sol
// ███████╗░█████╗░██████╗░██████╗░███████╗██████╗░░░░███████╗██╗// ╚════██║██╔══██╗██╔══██╗██╔══██╗██╔════╝██╔══██╗░░░██╔════╝██║// ░░███╔═╝███████║██████╔╝██████╔╝█████╗░░██████╔╝░░░█████╗░░██║// ██╔══╝░░██╔══██║██╔═══╝░██╔═══╝░██╔══╝░░██╔══██╗░░░██╔══╝░░██║// ███████╗██║░░██║██║░░░░░██║░░░░░███████╗██║░░██║██╗██║░░░░░██║// ╚══════╝╚═╝░░╚═╝╚═╝░░░░░╚═╝░░░░░╚══════╝╚═╝░░╚═╝╚═╝╚═╝░░░░░╚═╝// 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 Curve pools with ETH or ERC tokens.// SPDX-License-Identifier: GPL-2.0pragmasolidity ^0.8.0;import"../_base/ZapInBaseV3_1.sol";
interfaceIWETH{
functiondeposit() externalpayable;
}
interfaceICurveSwap{
functioncoins(int128 arg0) externalviewreturns (address);
functionunderlying_coins(int128 arg0) externalviewreturns (address);
functionadd_liquidity(uint256[4] calldata amounts, uint256 min_mint_amount)
external;
functionadd_liquidity(uint256[4] calldata amounts,
uint256 min_mint_amount,
bool addUnderlying
) external;
functionadd_liquidity(uint256[3] calldata amounts, uint256 min_mint_amount)
external;
functionadd_liquidity(uint256[3] calldata amounts,
uint256 min_mint_amount,
bool addUnderlying
) external;
functionadd_liquidity(uint256[2] calldata amounts, uint256 min_mint_amount)
external;
functionadd_liquidity(uint256[2] calldata amounts,
uint256 min_mint_amount,
bool addUnderlying
) external;
}
interfaceICurveEthSwap{
functionadd_liquidity(uint256[2] calldata amounts, uint256 min_mint_amount)
externalpayablereturns (uint256);
}
interfaceICurveRegistry{
functiongetSwapAddress(address tokenAddress)
externalviewreturns (address swapAddress);
functiongetTokenAddress(address swapAddress)
externalviewreturns (address tokenAddress);
functiongetDepositAddress(address swapAddress)
externalviewreturns (address depositAddress);
functiongetPoolTokens(address swapAddress)
externalviewreturns (address[4] memory poolTokens);
functionshouldAddUnderlying(address swapAddress)
externalviewreturns (bool);
functiongetNumTokens(address swapAddress)
externalviewreturns (uint8 numTokens);
functionisBtcPool(address swapAddress) externalviewreturns (bool);
functionisEthPool(address swapAddress) externalviewreturns (bool);
functionisUnderlyingToken(address swapAddress,
address tokenContractAddress
) externalviewreturns (bool, uint8);
}
contractCurve_ZapIn_General_V5isZapInBaseV3_1{
usingSafeERC20forIERC20;
ICurveRegistry public curveReg;
addressprivateconstant wethTokenAddress =0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
constructor(
ICurveRegistry _curveRegistry,
uint256 _goodwill,
uint256 _affiliateSplit
) ZapBaseV2_1(_goodwill, _affiliateSplit) {
curveReg = _curveRegistry;
// 0x exchange
approvedTargets[0xDef1C0ded9bec7F1a1670819833240f027b25EfF] =true;
}
eventzapIn(address sender,
address pool,
uint256 tokensRec,
address affiliate
);
/**
@notice This function adds liquidity to a Curve pool with ETH or ERC20 tokens
@param fromTokenAddress The token used for entry (address(0) if ether)
@param toTokenAddress The intermediate ERC20 token to swap to
@param swapAddress Curve swap address for the pool
@param incomingTokenQty The amount of fromTokenAddress to invest
@param minPoolTokens The minimum acceptable quantity of Curve LP to receive. Reverts otherwise
@param swapTarget Excecution target for the first swap
@param swapData DEX quote data
@param affiliate Affiliate address
@return crvTokensBought Quantity of Curve LP tokens received
*/functionZapIn(address fromTokenAddress,
address toTokenAddress,
address swapAddress,
uint256 incomingTokenQty,
uint256 minPoolTokens,
address swapTarget,
bytescalldata swapData,
address affiliate
) externalpayablestopInEmergencyreturns (uint256 crvTokensBought) {
uint256 toInvest =
_pullTokens(fromTokenAddress, incomingTokenQty, affiliate, true);
if (fromTokenAddress ==address(0)) {
fromTokenAddress = ETHAddress;
}
// perform zapIn
crvTokensBought = _performZapIn(
fromTokenAddress,
toTokenAddress,
swapAddress,
toInvest,
swapTarget,
swapData
);
require(
crvTokensBought > minPoolTokens,
"Received less than minPoolTokens"
);
address poolTokenAddress = curveReg.getTokenAddress(swapAddress);
emit zapIn(msg.sender, poolTokenAddress, crvTokensBought, affiliate);
IERC20(poolTokenAddress).transfer(msg.sender, crvTokensBought);
}
function_performZapIn(address fromTokenAddress,
address toTokenAddress,
address swapAddress,
uint256 toInvest,
address swapTarget,
bytesmemory swapData
) internalreturns (uint256 crvTokensBought) {
(bool isUnderlying, uint8 underlyingIndex) =
curveReg.isUnderlyingToken(swapAddress, fromTokenAddress);
if (isUnderlying) {
crvTokensBought = _enterCurve(
swapAddress,
toInvest,
underlyingIndex
);
} else {
//swap tokens using 0x swapuint256 tokensBought =
_fillQuote(
fromTokenAddress,
toTokenAddress,
toInvest,
swapTarget,
swapData
);
if (toTokenAddress ==address(0)) toTokenAddress = ETHAddress;
//get underlying token index
(isUnderlying, underlyingIndex) = curveReg.isUnderlyingToken(
swapAddress,
toTokenAddress
);
if (isUnderlying) {
crvTokensBought = _enterCurve(
swapAddress,
tokensBought,
underlyingIndex
);
} else {
(uint256 tokens, uint256 metaIndex) =
_enterMetaPool(swapAddress, toTokenAddress, tokensBought);
crvTokensBought = _enterCurve(swapAddress, tokens, metaIndex);
}
}
}
/**
@notice This function gets adds the liquidity for meta pools and returns the token index and swap tokens
@param swapAddress Curve swap address for the pool
@param toTokenAddress The ERC20 token to which from token to be convert
@param swapTokens quantity of toToken to invest
@return tokensBought quantity of curve LP acquired
@return index index of LP token in swapAddress whose pool tokens were acquired
*/function_enterMetaPool(address swapAddress,
address toTokenAddress,
uint256 swapTokens
) internalreturns (uint256 tokensBought, uint256 index) {
address[4] memory poolTokens = curveReg.getPoolTokens(swapAddress);
for (uint256 i =0; i <4; i++) {
address intermediateSwapAddress =
curveReg.getSwapAddress(poolTokens[i]);
if (intermediateSwapAddress !=address(0)) {
(, index) = curveReg.isUnderlyingToken(
intermediateSwapAddress,
toTokenAddress
);
tokensBought = _enterCurve(
intermediateSwapAddress,
swapTokens,
index
);
return (tokensBought, i);
}
}
}
function_fillQuote(address fromTokenAddress,
address toTokenAddress,
uint256 amount,
address swapTarget,
bytesmemory swapData
) internalreturns (uint256 amountBought) {
if (fromTokenAddress == toTokenAddress) {
return amount;
}
if (swapTarget == wethTokenAddress) {
IWETH(wethTokenAddress).deposit{ value: amount }();
return amount;
}
uint256 valueToSend;
if (fromTokenAddress == ETHAddress) {
valueToSend = amount;
} else {
_approveToken(fromTokenAddress, swapTarget, amount);
}
uint256 initialBalance = _getBalance(toTokenAddress);
require(approvedTargets[swapTarget], "Target not Authorized");
(bool success, ) = swapTarget.call{ value: valueToSend }(swapData);
require(success, "Error Swapping Tokens");
amountBought = _getBalance(toTokenAddress) - initialBalance;
require(amountBought >0, "Swapped To Invalid Intermediate");
}
/**
@notice This function adds liquidity to a curve pool
@param swapAddress Curve swap address for the pool
@param amount The quantity of tokens being added as liquidity
@param index The token index for the add_liquidity call
@return crvTokensBought the quantity of curve LP tokens received
*/function_enterCurve(address swapAddress,
uint256 amount,
uint256 index
) internalreturns (uint256 crvTokensBought) {
address tokenAddress = curveReg.getTokenAddress(swapAddress);
address depositAddress = curveReg.getDepositAddress(swapAddress);
uint256 initialBalance = _getBalance(tokenAddress);
address entryToken = curveReg.getPoolTokens(swapAddress)[index];
if (entryToken != ETHAddress) {
IERC20(entryToken).safeIncreaseAllowance(
address(depositAddress),
amount
);
}
uint256 numTokens = curveReg.getNumTokens(swapAddress);
bool addUnderlying = curveReg.shouldAddUnderlying(swapAddress);
if (numTokens ==4) {
uint256[4] memory amounts;
amounts[index] = amount;
if (addUnderlying) {
ICurveSwap(depositAddress).add_liquidity(amounts, 0, true);
} else {
ICurveSwap(depositAddress).add_liquidity(amounts, 0);
}
} elseif (numTokens ==3) {
uint256[3] memory amounts;
amounts[index] = amount;
if (addUnderlying) {
ICurveSwap(depositAddress).add_liquidity(amounts, 0, true);
} else {
ICurveSwap(depositAddress).add_liquidity(amounts, 0);
}
} else {
uint256[2] memory amounts;
amounts[index] = amount;
if (curveReg.isEthPool(depositAddress)) {
if (entryToken != ETHAddress) {
ICurveEthSwap(depositAddress).add_liquidity{ value: 0 }(
amounts,
0
);
} else {
ICurveEthSwap(depositAddress).add_liquidity{
value: amount
}(amounts, 0);
}
} elseif (addUnderlying) {
ICurveSwap(depositAddress).add_liquidity(amounts, 0, true);
} else {
ICurveSwap(depositAddress).add_liquidity(amounts, 0);
}
}
crvTokensBought = _getBalance(tokenAddress) - initialBalance;
}
functionupdateCurveRegistry(ICurveRegistry newCurveRegistry)
externalonlyOwner{
require(newCurveRegistry != curveReg, "Already using this Registry");
curveReg = newCurveRegistry;
}
}
Contract Source Code
File 4 of 9: IERC20.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.8.0;/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/interfaceIERC20{
/**
* @dev Returns the amount of tokens in existence.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/functionbalanceOf(address account) externalviewreturns (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.
*/functiontransfer(address recipient, uint256 amount)
externalreturns (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.
*/functionallowance(address owner, address spender)
externalviewreturns (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.
*/functionapprove(address spender, uint256 amount) externalreturns (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.
*/functiontransferFrom(address sender,
address recipient,
uint256 amount
) externalreturns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/eventTransfer(addressindexedfrom, addressindexed 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.
*/eventApproval(addressindexed owner,
addressindexed spender,
uint256 value
);
}
Contract Source Code
File 5 of 9: IERC20Metadata.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.8.0;import"../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/interfaceIERC20MetadataisIERC20{
/**
* @dev Returns the name of the token.
*/functionname() externalviewreturns (stringmemory);
/**
* @dev Returns the symbol of the token.
*/functionsymbol() externalviewreturns (stringmemory);
/**
* @dev Returns the decimals places of the token.
*/functiondecimals() externalviewreturns (uint8);
}
Contract Source Code
File 6 of 9: Ownable.sol
// SPDX-License-Identifier: MITpragmasolidity ^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.
*/abstractcontractOwnableisContext{
addressprivate _owner;
eventOwnershipTransferred(addressindexed previousOwner,
addressindexed 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.
*/functionowner() publicviewvirtualreturns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/modifieronlyOwner() {
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.
*/functionrenounceOwnership() publicvirtualonlyOwner{
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.
*/functiontransferOwnership(address newOwner) publicvirtualonlyOwner{
require(
newOwner !=address(0),
"Ownable: new owner is the zero address"
);
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
Contract Source Code
File 7 of 9: SafeERC20.sol
// SPDX-License-Identifier: MITpragmasolidity ^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.
*/librarySafeERC20{
usingAddressforaddress;
functionsafeTransfer(
IERC20 token,
address to,
uint256 value
) internal{
_callOptionalReturn(
token,
abi.encodeWithSelector(token.transfer.selector, to, value)
);
}
functionsafeTransferFrom(
IERC20 token,
addressfrom,
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.
*/functionsafeApprove(
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-lengthrequire(
(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)
);
}
functionsafeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal{
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(
token,
abi.encodeWithSelector(
token.approve.selector,
spender,
newAllowance
)
);
}
functionsafeDecreaseAllowance(
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, bytesmemory 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.bytesmemory returndata =address(token).functionCall(
data,
"SafeERC20: low-level call failed"
);
if (returndata.length>0) {
// Return data is optional// solhint-disable-next-line max-line-lengthrequire(
abi.decode(returndata, (bool)),
"SafeERC20: ERC20 operation did not succeed"
);
}
}
}