Contract Name:
RewardProgram
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.12;
pragma experimental ABIEncoderV2;
import "openzeppelin-solidity/contracts/token/ERC20/SafeERC20.sol";
import "openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";
import "openzeppelin-solidity/contracts/math/SafeMath.sol";
import "openzeppelin-solidity/contracts/access/Ownable.sol";
contract RewardProgram is Ownable {
using SafeMath for uint256;
using SafeERC20 for IERC20;
bytes32 public merkleRoot;
bool public cancelable;
IERC20 public tokenContract;
uint256 public fullRewardTimeoutPeriod = 180 days;
uint256 public shortRewardTimeoutPeriod = 30 days;
uint256 public shortRewardPercentage = 2;
uint256 public merkleRootLastUpdateTime;
uint256 public merkleRootLastUpdateBlock;
struct User {
string sidechainAddress;
bytes signature;
string message;
}
struct AmountWithTime {
uint amount;
uint timestamp;
bool isWithdrowedByNominator;
bool isFullWithdrawal;
}
mapping(address => uint256) public lastRewardRequestTime;
mapping(address => AmountWithTime[]) public requestedRewards;
mapping(address => AmountWithTime[]) public receivedRewards;
mapping(address => mapping(string => User)) private ethereumAddressOnSidechainAddress;
mapping(string => mapping(address => User)) private sidechainAddressOnEthereumAddress;
modifier isCancelable() {
require(!cancelable, "forbidden action");
_;
}
event AddLink (address indexed ethereumAddress, string target, bytes signature, string message);
event RequestReward (address target, uint amount, bool isFullWithdrawal);
event ReceiveReward (address target, uint amount, bool indexed isWithdrowedByNominator);
event UpdateMerkleRoot (bytes32 merkleRoot);
function sidechainUser(address ethereumAddress, string memory target) public view returns (User memory) {
return ethereumAddressOnSidechainAddress[ethereumAddress][target];
}
function ethereumUser(address ethereumAddress, string memory target) public view returns (User memory) {
return sidechainAddressOnEthereumAddress[target][ethereumAddress];
}
function contractTokenBalance() public view returns(uint) {
return tokenContract.balanceOf(address(this));
}
function getRequestedRewardArray(address target) public view returns(AmountWithTime[] memory) {
return requestedRewards[target];
}
function getReceivedRewardArray(address target) public view returns(AmountWithTime[] memory) {
return receivedRewards[target];
}
constructor(address _tokenContract, bool _cancelable) public {
tokenContract = IERC20(_tokenContract);
cancelable = _cancelable;
}
function setCancelable(bool _cancelable) public onlyOwner {
cancelable = _cancelable;
}
function setFullRewardTimeoutPeriod(uint256 period) public onlyOwner {
fullRewardTimeoutPeriod = period;
}
function setShortRewardTimeoutPeriod(uint256 period) public onlyOwner {
shortRewardTimeoutPeriod = period;
}
function setShortRewardPercentage(uint256 percentage) public onlyOwner {
shortRewardPercentage = percentage;
}
function linkAddresses(string memory target, bytes memory signature, string memory message) public {
User memory user = User(target, signature, message);
ethereumAddressOnSidechainAddress[msg.sender][target] = user;
sidechainAddressOnEthereumAddress[target][msg.sender] = user;
emit AddLink(msg.sender, target, signature, message);
}
function setRoot(bytes32 _merkleRoot, uint256 amount) public onlyOwner {
address ownContractAddress = address(this);
if (amount > 0) {
require(tokenContract.allowance(owner(), ownContractAddress) >= amount, "approved balance not enough");
tokenContract.transferFrom(owner(), ownContractAddress, amount);
}
merkleRoot = _merkleRoot;
merkleRootLastUpdateTime = block.timestamp;
merkleRootLastUpdateBlock = block.number;
cancelable = false;
emit UpdateMerkleRoot(_merkleRoot);
}
function requestReward(uint256 amount, bool isFullWithdrawal) internal returns (bool) {
uint timestamp = block.timestamp;
lastRewardRequestTime[msg.sender] = timestamp;
requestedRewards[msg.sender].push(AmountWithTime(amount, timestamp, false, isFullWithdrawal));
emit RequestReward(msg.sender, amount, isFullWithdrawal);
return true;
}
function calculateShortAmount(uint amount) internal view returns(uint) {
return amount.mul(shortRewardPercentage).div(10);
}
function getRequestAmountWithError(address target, uint item) internal view returns(uint amount, uint timestamp, bool isWithdrowedByNominator, bool isFullWithdrawal) {
require(item < requestedRewards[target].length, "item is not exist");
AmountWithTime storage request = requestedRewards[target][item];
uint256 fullAmount = request.amount;
uint256 fullTimestamp = request.timestamp;
bool fullWithdrawal = request.isFullWithdrawal;
uint256 timePeriod = fullWithdrawal ? fullRewardTimeoutPeriod : shortRewardTimeoutPeriod;
require(fullAmount > 0, "item is empty");
require(block.timestamp >= fullTimestamp + timePeriod, "expiration period is not over");
amount = fullAmount;
timestamp = request.timestamp;
isWithdrowedByNominator = request.isWithdrowedByNominator;
isFullWithdrawal = fullWithdrawal;
}
function transferOrApproveRewardToAddress(address target, uint amount, bool isWithdrowedByNominator, bool isApprove, bool isFullWithdrawal) internal {
receivedRewards[target].push(AmountWithTime(amount, block.timestamp, isWithdrowedByNominator, isFullWithdrawal));
if (isApprove) {
tokenContract.approve(target, amount);
} else {
tokenContract.transfer(target, amount);
}
emit ReceiveReward(target, amount, isWithdrowedByNominator);
}
function receiveResidue(address target, uint item, address receiver) public onlyOwner {
(uint amount, uint timestamp, bool isWithdrowedByNominator, bool isFullWithdrawal) = getRequestAmountWithError(target, item);
require(isWithdrowedByNominator, "reward is not received by user");
require(contractTokenBalance() >= amount, "not enough balance");
delete requestedRewards[target][item];
bool isApprove = true;
transferOrApproveRewardToAddress(receiver, amount, false, isApprove, isFullWithdrawal);
}
function receiveReward(uint item) public {
address target = msg.sender;
(uint fullAmount, uint timestamp, bool isWithdrowedByNominator, bool isFullWithdrawal) = getRequestAmountWithError(target, item);
require(!isWithdrowedByNominator, "reward already received");
uint amount = fullAmount;
uint residue = 0;
if (!isFullWithdrawal) {
amount = calculateShortAmount(fullAmount);
residue = fullAmount.sub(amount);
}
require(contractTokenBalance() >= amount, "not enough balance");
AmountWithTime storage request = requestedRewards[target][item];
if (!isFullWithdrawal) {
request.isWithdrowedByNominator = true;
request.amount = residue;
request.isFullWithdrawal = true;
request.timestamp = block.timestamp;
} else {
delete requestedRewards[target][item];
}
bool isApprove = false;
transferOrApproveRewardToAddress(target, amount, true, isApprove, isFullWithdrawal);
}
function transferAllTokensToOwner() public onlyOwner returns(bool) {
tokenContract.transfer(owner(), contractTokenBalance());
return true;
}
function leafFromAddressAndAmount(address _a, uint256 _n) internal pure returns(bytes32) {
return keccak256(abi.encodePacked(_a, _n));
}
function checkProof(bytes32[] memory proof, bytes32 hash) internal view returns (bool) {
bytes32 el;
bytes32 h = hash;
for (uint i = 0; i <= proof.length - 1; i += 1) {
el = proof[i];
if (h <= el) {
h = keccak256(abi.encodePacked(h, el));
} else {
h = keccak256(abi.encodePacked(el, h));
}
}
return h == merkleRoot;
}
function requestTokensByMerkleProof(bytes32[] memory _proof, uint256 _amount, bool _isFullWithdrawal) public isCancelable returns(bool) {
require(lastRewardRequestTime[msg.sender] < merkleRootLastUpdateTime, "already withdrawn in this period");
require(_amount > 0, "amount should be not zero");
if (!_isFullWithdrawal) {
require(calculateShortAmount(_amount) > 0, "amount too low");
}
require(checkProof(_proof, leafFromAddressAndAmount(msg.sender, _amount)), "proof is not correct");
return requestReward(_amount, _isFullWithdrawal);
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=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.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../GSN/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 () internal {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view 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 >=0.6.0 <0.8.0;
/**
* @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.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (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.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (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/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts 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.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message 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.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts 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.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message 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.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <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 >=0.6.0 <0.8.0;
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.
*/
library SafeERC20 {
using SafeMath for uint256;
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).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(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, 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 >=0.6.2 <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);
}
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);
}
}
}
}