// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;/**
* @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 10: Context.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <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 GSN 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 (addresspayable) {
returnmsg.sender;
}
function_msgData() internalviewvirtualreturns (bytesmemory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691returnmsg.data;
}
}
Contract Source Code
File 3 of 10: DAOFarm.sol
// SPDX-License-Identifier: MIT// DAOSworld:// Create custom reward pools to incentivize stakers of any ERC20!// https://twitter.com/Daosdotworldpragmasolidity =0.7.6;pragmaabicoderv2;import"openzeppelin-contracts/math/SafeMath.sol";
import"openzeppelin-contracts/token/ERC20/SafeERC20.sol";
import"openzeppelin-contracts/token/ERC20/IERC20.sol";
import"openzeppelin-contracts/utils/EnumerableSet.sol";
import"openzeppelin-contracts/utils/ReentrancyGuard.sol";
import"openzeppelin-contracts/access/Ownable.sol";
import {IDAOFarmFactory} from"./DAOFarmFactory.sol";
contractDAOFarmisReentrancyGuard, Ownable{
usingEnumerableSetforEnumerableSet.UintSet;
usingEnumerableSetforEnumerableSet.AddressSet;
usingSafeERC20forIERC20;
usingSafeMathforuint256;
structUserInfo {
uint256 totalDepositAmount; // Save total deposit amountuint256 rewardDebtToken1;
}
structSettings {
uint256 startTime; // Start of rewards distributionuint256 endTime; // End of rewards distribution
}
structRewardsToken {
IERC20 token;
uint256 amount; // Total rewards to distributeuint256 remainingAmount; // Remaining rewards to distributeuint256 accRewardsPerShare;
}
IDAOFarmFactory public factory;
uint256public creationTime; // Creation time of this DAOfarm.solboolpublic emergencyClose; // When activated, can't distribute rewards anymore
IERC20 public depositToken;
RewardsToken public rewardsToken1; // rewardsToken1 data// pool infouint256public totalDepositAmount;
uint256public lastRewardTime;
mapping(address=> UserInfo) public userInfo;
Settings public settings; // global and requirements settingsconstructor(address owner_, IERC20 depositToken_, IERC20 rewardsToken1_, Settings memory settings_) {
require(_currentBlockTimestamp() < settings_.startTime, "invalid startTime");
require(settings_.startTime < settings_.endTime, "invalid endTime");
factory = IDAOFarmFactory(msg.sender);
creationTime = _currentBlockTimestamp();
depositToken = depositToken_;
rewardsToken1.token = rewardsToken1_;
settings.startTime = settings_.startTime;
settings.endTime = settings_.endTime;
lastRewardTime = settings_.startTime;
Ownable.transferOwnership(owner_);
}
eventActivateEmergencyClose();
eventAddRewardsToken1(uint256 amount, uint256 feeAmount);
eventDeposit(addressindexed userAddress, uint256 amount);
eventHarvest(addressindexed userAddress, IERC20 rewardsToken, uint256 pending);
eventSetDateSettings(uint256 endTime);
eventUpdatePool();
eventWithdraw(addressindexed userAddress, uint256 amount);
eventEmergencyWithdraw(addressindexed userAddress, uint256 amount);
eventWithdrawRewardsToken1(uint256 amount, uint256 totalRewardsAmount);
/**
* @dev Returns the amount of rewardsToken1 distributed every second
*/functionrewardsToken1PerSecond() publicviewreturns (uint256) {
if (settings.endTime <= lastRewardTime) return0;
return rewardsToken1.remainingAmount.div(settings.endTime.sub(lastRewardTime));
}
/**
* @dev Returns pending rewards (rewardsToken1) for "account" address
*/functionpendingRewards(address account) externalviewreturns (uint256 pending1) {
UserInfo memory user = userInfo[account];
// recompute accRewardsPerShare for rewardsToken1 if not up to dateuint256 accRewardsToken1PerShare_ = rewardsToken1.accRewardsPerShare;
// only if existing deposits and lastRewardTime already passedif (lastRewardTime < _currentBlockTimestamp() && totalDepositAmount >0) {
uint256 rewardsAmount = rewardsToken1PerSecond().mul(_currentBlockTimestamp().sub(lastRewardTime));
// in case of rounding errorsif (rewardsAmount > rewardsToken1.remainingAmount) rewardsAmount = rewardsToken1.remainingAmount;
accRewardsToken1PerShare_ = accRewardsToken1PerShare_.add(rewardsAmount.mul(1e18).div(totalDepositAmount));
}
pending1 = (user.totalDepositAmount.mul(accRewardsToken1PerShare_).div(1e18).sub(user.rewardDebtToken1));
}
/**
* @dev Update this DAOFarm.sol
*/functionupdatePool() externalnonReentrant{
_updatePool();
}
functiondeposit(uint256 amount) external{
require((settings.endTime >= _currentBlockTimestamp()) &&!emergencyClose, "not allowed");
uint256 balanceBefore = IERC20(depositToken).balanceOf(address(this));
IERC20(depositToken).transferFrom(msg.sender, address(this), amount);
_deposit(msg.sender, amount);
require(balanceBefore + amount >= IERC20(depositToken).balanceOf(address(this)), "Likely a fee on transfer error");
}
functionwithdraw(uint256 amount) externalvirtualnonReentrant{
_updatePool();
UserInfo storage user = userInfo[msg.sender];
require(user.totalDepositAmount >= amount, "Withdrawing too much");
_harvest(user, msg.sender);
user.totalDepositAmount = user.totalDepositAmount.sub(amount);
totalDepositAmount = totalDepositAmount.sub(amount);
_updateRewardDebt(user);
IERC20(depositToken).transfer(msg.sender, amount);
emit Withdraw(msg.sender, amount);
}
functionemergencyWithdraw() externalvirtualnonReentrant{
UserInfo storage user = userInfo[msg.sender];
uint256 amount = user.totalDepositAmount;
user.totalDepositAmount = user.totalDepositAmount.sub(amount);
totalDepositAmount = totalDepositAmount.sub(amount);
_updateRewardDebt(user);
IERC20(depositToken).transfer(msg.sender, amount);
emit EmergencyWithdraw(msg.sender, amount);
}
/**
* @dev Harvest pending DAOFarm.sol rewards
*/functionharvest() externalnonReentrant{
_updatePool();
UserInfo storage user = userInfo[msg.sender];
_harvest(user, msg.sender);
_updateRewardDebt(user);
}
/**
* @dev Transfer ownership of this DAOfarm.sol
*
* Must only be called by the owner of this contract
*/functiontransferOwnership(address newOwner) publicoverrideonlyOwner{
_setNitroPoolOwner(newOwner);
Ownable.transferOwnership(newOwner);
}
/**
* @dev Transfer ownership of this DAOfarm.sol
*
* Must only be called by the owner of this contract
*/functionrenounceOwnership() publicoverrideonlyOwner{
_setNitroPoolOwner(address(0));
Ownable.renounceOwnership();
}
/**
* @dev Add rewards to this DAOfarm.sol
*/functionaddRewards(uint256 amountToken1) externalnonReentrant{
require(_currentBlockTimestamp() < settings.endTime, "pool ended");
_updatePool();
// get active fee share for this DAOfarm.soluint256 feeShare = factory.getNitroPoolFee(address(this), owner());
address feeAddress = factory.feeAddress();
uint256 feeAmount;
if (amountToken1 >0) {
// token1 fee
feeAmount = amountToken1.mul(feeShare).div(10000);
amountToken1 =
_transferSupportingFeeOnTransfer(rewardsToken1.token, msg.sender, amountToken1.sub(feeAmount));
// recomputes rewards to distribute
rewardsToken1.amount = rewardsToken1.amount.add(amountToken1);
rewardsToken1.remainingAmount = rewardsToken1.remainingAmount.add(amountToken1);
emit AddRewardsToken1(amountToken1, feeAmount);
if (feeAmount >0) {
rewardsToken1.token.safeTransferFrom(msg.sender, feeAddress, feeAmount);
}
}
}
/**
* @dev Withdraw rewards from this DAOfarm.sol
*
* Must only be called by the owner
* Must only be called before the start time of the Nitro Pool
*/functionwithdrawRewards(uint256 amountToken1) externalonlyOwnernonReentrant{
require(block.timestamp< settings.startTime);
if (amountToken1 >0) {
// recomputes rewards to distribute
rewardsToken1.amount = rewardsToken1.amount.sub(amountToken1, "too high");
rewardsToken1.remainingAmount = rewardsToken1.remainingAmount.sub(amountToken1, "too high");
emit WithdrawRewardsToken1(amountToken1, rewardsToken1.amount);
_safeRewardsTransfer(rewardsToken1.token, msg.sender, amountToken1);
}
}
/**
* @dev Set the pool's datetime settings
*
* Must only be called by the owner
*/functionsetDateSettings(uint256 endTime_) externalnonReentrantonlyOwner{
require(settings.startTime < endTime_, "invalid endTime");
require(_currentBlockTimestamp() <= settings.endTime, "pool ended");
settings.endTime = endTime_;
emit SetDateSettings(endTime_);
}
/**
* @dev Emergency close
*
* Must only be called by the owner
* Emergency only: if used, the whole pool is definitely made void
* All rewards are automatically transferred to the emergency recovery address
*/functionactivateEmergencyClose() externalnonReentrantonlyOwner{
address emergencyRecoveryAddress = factory.emergencyRecoveryAddress();
uint256 remainingToken1 = rewardsToken1.remainingAmount;
rewardsToken1.amount = rewardsToken1.amount.sub(remainingToken1);
rewardsToken1.remainingAmount =0;
emergencyClose =true;
emit ActivateEmergencyClose();
// transfer rewardsToken1 remaining amount if any
_safeRewardsTransfer(rewardsToken1.token, emergencyRecoveryAddress, remainingToken1);
}
/**
* @dev Updates rewards states of this Nitro Pool to be up-to-date
*/function_updatePool() internal{
uint256 currentBlockTimestamp = _currentBlockTimestamp();
if (currentBlockTimestamp <= lastRewardTime) return;
// do nothing if there is no depositif (totalDepositAmount ==0) {
lastRewardTime = currentBlockTimestamp;
emit UpdatePool();
return;
}
// updates rewardsToken1 stateuint256 rewardsAmount = rewardsToken1PerSecond().mul(currentBlockTimestamp.sub(lastRewardTime));
// ensure we do not distribute more than what's availableif (rewardsAmount > rewardsToken1.remainingAmount) rewardsAmount = rewardsToken1.remainingAmount;
rewardsToken1.remainingAmount = rewardsToken1.remainingAmount.sub(rewardsAmount);
rewardsToken1.accRewardsPerShare =
rewardsToken1.accRewardsPerShare.add(rewardsAmount.mul(1e18).div(totalDepositAmount));
lastRewardTime = currentBlockTimestamp;
emit UpdatePool();
}
/**
* @dev Add a user's deposited amount into this Nitro Pool
*/function_deposit(address account, uint256 amount) internal{
_updatePool();
UserInfo storage user = userInfo[account];
_harvest(user, account);
user.totalDepositAmount = user.totalDepositAmount.add(amount);
totalDepositAmount = totalDepositAmount.add(amount);
_updateRewardDebt(user);
emit Deposit(account, amount);
}
/**
* @dev Transfer to a user its pending rewards
*/function_harvest(UserInfo storage user, address to) internal{
uint256 pending =
user.totalDepositAmount.mul(rewardsToken1.accRewardsPerShare).div(1e18).sub(user.rewardDebtToken1);
_safeRewardsTransfer(rewardsToken1.token, to, pending);
emit Harvest(to, rewardsToken1.token, pending);
}
/**
* @dev Update a user's rewardDebt for rewardsToken1
*/function_updateRewardDebt(UserInfo storage user) internalvirtual{
(bool succeed, uint256 result) = user.totalDepositAmount.tryMul(rewardsToken1.accRewardsPerShare);
if (succeed) user.rewardDebtToken1 = result.div(1e18);
}
/**
* @dev Handle deposits of tokens with transfer tax
*/function_transferSupportingFeeOnTransfer(IERC20 token, address user, uint256 amount)
internalreturns (uint256 receivedAmount)
{
uint256 previousBalance = token.balanceOf(address(this));
token.safeTransferFrom(user, address(this), amount);
return token.balanceOf(address(this)).sub(previousBalance);
}
/**
* @dev Safe token transfer function, in case rounding error causes pool to not have enough tokens
*/function_safeRewardsTransfer(IERC20 token, address to, uint256 amount) internalvirtual{
if (amount ==0) return;
uint256 balance = token.balanceOf(address(this));
// cap to available balanceif (amount > balance) {
amount = balance;
}
token.safeTransfer(to, amount);
}
function_setNitroPoolOwner(address newOwner) internal{
factory.setNitroPoolOwner(owner(), newOwner);
}
/**
* @dev Utility function to get the current block timestamp
*/function_currentBlockTimestamp() internalviewvirtualreturns (uint256) {
/* solhint-disable not-rely-on-time */returnblock.timestamp;
}
}
Contract Source Code
File 4 of 10: DAOFarmFactory.sol
// SPDX-License-Identifier: MIT// DAOFarm:// Create custom reward pools to incentivize stakers of any ERC20!// https://twitter.com/Daosdotworldpragmasolidity =0.7.6;pragmaabicoderv2;import"openzeppelin-contracts/access/Ownable.sol";
import"openzeppelin-contracts/token/ERC20/IERC20.sol";
import"openzeppelin-contracts/utils/EnumerableSet.sol";
import"./DAOFarm.sol";
interfaceIDAOFarmFactory{
functionemergencyRecoveryAddress() externalviewreturns (address);
functionfeeAddress() externalviewreturns (address);
functiongetNitroPoolFee(address nitroPoolAddress, address ownerAddress) externalviewreturns (uint256);
functionsetNitroPoolOwner(address previousOwner, address newOwner) external;
}
contractDAOFarmFactoryisOwnable, IDAOFarmFactory{
usingEnumerableSetforEnumerableSet.AddressSet;
EnumerableSet.AddressSet internal _nitroPools; // all nitro poolsmapping(address=> EnumerableSet.AddressSet) internal _ownerNitroPools; // nitro pools per owneruint256publicconstant MAX_DEFAULT_FEE =500; // (1%) max authorized default feeuint256public defaultFee; // default fee for nitro pools (*1e2)addresspublicoverride feeAddress; // to receive fees when defaultFee is set
EnumerableSet.AddressSet internal _exemptedAddresses; // owners or nitro addresses exempted from default feeaddresspublicoverride emergencyRecoveryAddress; // to recover rewards from emergency closed nitro poolsconstructor(address emergencyRecoveryAddress_, address feeAddress_) {
require(emergencyRecoveryAddress_ !=address(0) && feeAddress_ !=address(0), "invalid");
emergencyRecoveryAddress = emergencyRecoveryAddress_;
feeAddress = feeAddress_;
}
eventCreateNitroPool(address nitroAddress);
eventSetDefaultFee(uint256 fee);
eventSetFeeAddress(address feeAddress);
eventSetEmergencyRecoveryAddress(address emergencyRecoveryAddress);
eventSetExemptedAddress(address exemptedAddress, bool isExempted);
eventSetNitroPoolOwner(address previousOwner, address newOwner);
modifiernitroPoolExists(address nitroPoolAddress) {
require(_nitroPools.contains(nitroPoolAddress), "unknown nitroPool");
_;
}
/**
* @dev Returns the number of nitroPools
*/functionnitroPoolsLength() externalviewreturns (uint256) {
return _nitroPools.length();
}
/**
* @dev Returns a nitroPool from its "index"
*/functiongetNitroPool(uint256 index) externalviewreturns (address) {
return _nitroPools.at(index);
}
/**
* @dev Returns the number of nitroPools owned by "userAddress"
*/functionownerNitroPoolsLength(address userAddress) externalviewreturns (uint256) {
return _ownerNitroPools[userAddress].length();
}
/**
* @dev Returns a nitroPool owned by "userAddress" from its "index"
*/functiongetOwnerNitroPool(address userAddress, uint256 index) externalviewreturns (address) {
return _ownerNitroPools[userAddress].at(index);
}
/**
* @dev Returns the number of exemptedAddresses
*/functionexemptedAddressesLength() externalviewreturns (uint256) {
return _exemptedAddresses.length();
}
/**
* @dev Returns an exemptedAddress from its "index"
*/functiongetExemptedAddress(uint256 index) externalviewreturns (address) {
return _exemptedAddresses.at(index);
}
/**
* @dev Returns if a given address is in exemptedAddresses
*/functionisExemptedAddress(address checkedAddress) externalviewreturns (bool) {
return _exemptedAddresses.contains(checkedAddress);
}
/**
* @dev Returns the fee for "nitroPoolAddress" address
*/functiongetNitroPoolFee(address nitroPoolAddress, address ownerAddress) externalviewoverridereturns (uint256) {
if (_exemptedAddresses.contains(nitroPoolAddress) || _exemptedAddresses.contains(ownerAddress)) {
return0;
}
return defaultFee;
}
/**
* @dev Deploys a new Nitro Pool
*/functioncreateNitroPool(IERC20 depositToken, IERC20 rewardsToken1, DAOFarm.Settings calldata settings)
externalvirtualreturns (address nitroPool)
{
// Initialize new nitro pool
nitroPool =address(new DAOFarm(msg.sender, depositToken, rewardsToken1, settings));
// Add new nitro
_nitroPools.add(nitroPool);
_ownerNitroPools[msg.sender].add(nitroPool);
emit CreateNitroPool(nitroPool);
}
/**
* @dev Transfers a Nitro Pool's ownership
*
* Must only be called by the DAOFarm.sol contract
*/functionsetNitroPoolOwner(address previousOwner, address newOwner) externaloverridenitroPoolExists(msg.sender) {
require(_ownerNitroPools[previousOwner].remove(msg.sender), "invalid owner");
_ownerNitroPools[newOwner].add(msg.sender);
emit SetNitroPoolOwner(previousOwner, newOwner);
}
/**
* @dev Set nitroPools default fee (when adding rewards)
*
* Must only be called by the owner
*/functionsetDefaultFee(uint256 newFee) externalonlyOwner{
require(newFee <= MAX_DEFAULT_FEE, "invalid amount");
defaultFee = newFee;
emit SetDefaultFee(newFee);
}
/**
* @dev Set fee address
*
* Must only be called by the owner
*/functionsetFeeAddress(address feeAddress_) externalonlyOwner{
require(feeAddress_ !=address(0), "zero address");
feeAddress = feeAddress_;
emit SetFeeAddress(feeAddress_);
}
/**
* @dev Add or remove exemptedAddresses
*
* Must only be called by the owner
*/functionsetExemptedAddress(address exemptedAddress, bool isExempted) externalonlyOwner{
require(exemptedAddress !=address(0), "zero address");
if (isExempted) _exemptedAddresses.add(exemptedAddress);
else _exemptedAddresses.remove(exemptedAddress);
emit SetExemptedAddress(exemptedAddress, isExempted);
}
/**
* @dev Set emergencyRecoveryAddress
*
* Must only be called by the owner
*/functionsetEmergencyRecoveryAddress(address emergencyRecoveryAddress_) externalonlyOwner{
require(emergencyRecoveryAddress_ !=address(0), "zero address");
emergencyRecoveryAddress = emergencyRecoveryAddress_;
emit SetEmergencyRecoveryAddress(emergencyRecoveryAddress_);
}
/**
* @dev Utility function to get the current block timestamp
*/function_currentBlockTimestamp() internalviewvirtualreturns (uint256) {
/* solhint-disable not-rely-on-time */returnblock.timestamp;
}
}
Contract Source Code
File 5 of 10: EnumerableSet.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;/**
* @dev Library for managing
* https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
* types.
*
* Sets have the following properties:
*
* - Elements are added, removed, and checked for existence in constant time
* (O(1)).
* - Elements are enumerated in O(n). No guarantees are made on the ordering.
*
* ```
* contract Example {
* // Add the library methods
* using EnumerableSet for EnumerableSet.AddressSet;
*
* // Declare a set state variable
* EnumerableSet.AddressSet private mySet;
* }
* ```
*
* As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
* and `uint256` (`UintSet`) are supported.
*/libraryEnumerableSet{
// To implement this library for multiple types with as little code// repetition as possible, we write it in terms of a generic Set type with// bytes32 values.// The Set implementation uses private functions, and user-facing// implementations (such as AddressSet) are just wrappers around the// underlying Set.// This means that we can only create new EnumerableSets for types that fit// in bytes32.structSet {
// Storage of set valuesbytes32[] _values;
// Position of the value in the `values` array, plus 1 because index 0// means a value is not in the set.mapping (bytes32=>uint256) _indexes;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/function_add(Set storage set, bytes32 value) privatereturns (bool) {
if (!_contains(set, value)) {
set._values.push(value);
// The value is stored at length-1, but we add 1 to all indexes// and use 0 as a sentinel value
set._indexes[value] = set._values.length;
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/function_remove(Set storage set, bytes32 value) privatereturns (bool) {
// We read and store the value's index to prevent multiple reads from the same storage slotuint256 valueIndex = set._indexes[value];
if (valueIndex !=0) { // Equivalent to contains(set, value)// To delete an element from the _values array in O(1), we swap the element to delete with the last one in// the array, and then remove the last element (sometimes called as 'swap and pop').// This modifies the order of the array, as noted in {at}.uint256 toDeleteIndex = valueIndex -1;
uint256 lastIndex = set._values.length-1;
// When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs// so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.bytes32 lastvalue = set._values[lastIndex];
// Move the last value to the index where the value to delete is
set._values[toDeleteIndex] = lastvalue;
// Update the index for the moved value
set._indexes[lastvalue] = toDeleteIndex +1; // All indexes are 1-based// Delete the slot where the moved value was stored
set._values.pop();
// Delete the index for the deleted slotdelete set._indexes[value];
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Returns true if the value is in the set. O(1).
*/function_contains(Set storage set, bytes32 value) privateviewreturns (bool) {
return set._indexes[value] !=0;
}
/**
* @dev Returns the number of values on the set. O(1).
*/function_length(Set storage set) privateviewreturns (uint256) {
return set._values.length;
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/function_at(Set storage set, uint256 index) privateviewreturns (bytes32) {
require(set._values.length> index, "EnumerableSet: index out of bounds");
return set._values[index];
}
// Bytes32SetstructBytes32Set {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(Bytes32Set storage set, bytes32 value) internalreturns (bool) {
return _add(set._inner, value);
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(Bytes32Set storage set, bytes32 value) internalreturns (bool) {
return _remove(set._inner, value);
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(Bytes32Set storage set, bytes32 value) internalviewreturns (bool) {
return _contains(set._inner, value);
}
/**
* @dev Returns the number of values in the set. O(1).
*/functionlength(Bytes32Set storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(Bytes32Set storage set, uint256 index) internalviewreturns (bytes32) {
return _at(set._inner, index);
}
// AddressSetstructAddressSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(AddressSet storage set, address value) internalreturns (bool) {
return _add(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(AddressSet storage set, address value) internalreturns (bool) {
return _remove(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(AddressSet storage set, address value) internalviewreturns (bool) {
return _contains(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns the number of values in the set. O(1).
*/functionlength(AddressSet storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(AddressSet storage set, uint256 index) internalviewreturns (address) {
returnaddress(uint160(uint256(_at(set._inner, index))));
}
// UintSetstructUintSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(UintSet storage set, uint256 value) internalreturns (bool) {
return _add(set._inner, bytes32(value));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(UintSet storage set, uint256 value) internalreturns (bool) {
return _remove(set._inner, bytes32(value));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(UintSet storage set, uint256 value) internalviewreturns (bool) {
return _contains(set._inner, bytes32(value));
}
/**
* @dev Returns the number of values on the set. O(1).
*/functionlength(UintSet storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(UintSet storage set, uint256 index) internalviewreturns (uint256) {
returnuint256(_at(set._inner, index));
}
}
Contract Source Code
File 6 of 10: IERC20.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;/**
* @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 7 of 10: Ownable.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;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 8 of 10: ReentrancyGuard.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;/**
* @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].
*/abstractcontractReentrancyGuard{
// 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.uint256privateconstant _NOT_ENTERED =1;
uint256privateconstant _ENTERED =2;
uint256private _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 make it call a
* `private` function that does the actual work.
*/modifiernonReentrant() {
// On the first call to nonReentrant, _notEntered will be truerequire(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
Contract Source Code
File 9 of 10: SafeERC20.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;import"./IERC20.sol";
import"../../math/SafeMath.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{
usingSafeMathforuint256;
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).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
functionsafeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal{
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_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");
}
}
}
Contract Source Code
File 10 of 10: SafeMath.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.7.0;/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/librarySafeMath{
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryAdd(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontrySub(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryMul(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the// benefit is lost if 'b' is also tested.// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522if (a ==0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryDiv(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b ==0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryMod(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b ==0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/functionadd(uint256 a, uint256 b) internalpurereturns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/functionmul(uint256 a, uint256 b) internalpurereturns (uint256) {
if (a ==0) return0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b >0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b >0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b >0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b >0, errorMessage);
return a % b;
}
}