Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "./Signature.sol";
contract TGE is Ownable, Signature {
using SafeERC20 for IERC20;
/** @dev Terms and conditions as a keccak256 hash */
string public constant termsAndConditions =
"By signing this message I agree to the $FOREX TOKEN - TERMS AND CONDITIONS identified by the hash: 0x1b42a1c6369d3efbf3b65d757e3f5e804bc26935b45dda1eaf0d90ef297289b4";
/** @dev ERC-191 encoded Terms and Conditions for signature validation */
bytes32 private constant termsAndConditionsERC191 =
keccak256(
abi.encodePacked(
bytes1(0x19),
bytes1("E"),
bytes("thereum Signed Message:\n165"),
abi.encodePacked(termsAndConditions)
)
);
/** @dev Error message for claiming before allowed period */
string private constant notClaimable = "Funds not yet claimable";
/** @dev The amount of FOREX to be generated */
uint256 public constant forexAmount = 20_760_000 ether;
/** @dev The address of this contract's deployed instance */
address private immutable self;
/** @dev Canonical FOREX token address */
address public immutable FOREX;
/** @dev Per-user deposit cap */
uint256 public immutable userCap;
/** @dev Minimum token price in ETH (soft cap parameter) */
uint256 public minTokenPrice;
/** @dev Maximum token price in ETH (if hard cap is met) */
uint256 public maxTokenPrice;
/** @dev Generation duration (seconds) */
uint256 public immutable generationDuration;
/** @dev Start date for the generation; when ETH deposits are accepted */
uint256 public immutable generationStartDate;
/** @dev Maximum deposit cap in ETH from which new deposits are ignored */
uint256 public depositCap;
/** @dev Date from when FOREX claiming is allowed */
uint256 public claimDate;
/** @dev Amount of ETH deposited during the TGE */
uint256 public ethDeposited;
/** @dev Mapping of (depositor => eth amount) for the TGE period */
mapping(address => uint256) private deposits;
/** @dev Mapping of (depositor => T&Cs signature status) */
mapping(address => bool) public signedTermsAndConditions;
/** @dev Mapping of (depositor => claimed eth) */
mapping(address => bool) private claimedEth;
/** @dev Mapping of (depositor => claimed forex) */
mapping(address => bool) private claimedForex;
/** @dev The total ETH deposited under a referral address */
mapping(address => uint256) public referrerDeposits;
/** @dev Number of depositors */
uint256 public depositorCount;
/** @dev Whether leftover FOREX tokens were withdrawn by owner
(only possible if FOREX did not reach the max price) */
bool private withdrawnRemainingForex;
/** @dev Whether the TGE was aborted by the owner */
bool private aborted;
/** @dev ETH withdrawn by owner */
uint256 public ethWithdrawnByOwner;
modifier notAborted() {
require(!aborted, "TGE aborted");
_;
}
constructor(
address _FOREX,
uint256 _userCap,
uint256 _depositCap,
uint256 _minTokenPrice,
uint256 _maxTokenPrice,
uint256 _generationDuration,
uint256 _generationStartDate
) {
require(_generationDuration > 0, "Duration must be > 0");
require(
_generationStartDate > block.timestamp,
"Start date must be in the future"
);
self = address(this);
FOREX = _FOREX;
userCap = _userCap;
depositCap = _depositCap;
minTokenPrice = _minTokenPrice;
maxTokenPrice = _maxTokenPrice;
generationDuration = _generationDuration;
generationStartDate = _generationStartDate;
}
/**
* @dev Deny direct ETH transfers.
*/
receive() external payable {
revert("Must call deposit to participate");
}
/**
* @dev Validates a signature for the hashed terms & conditions message.
* The T&Cs hash is converted to an ERC-191 message before verifying.
* @param signature The signature to validate.
*/
function signTermsAndConditions(bytes memory signature) public {
if (signedTermsAndConditions[msg.sender]) return;
address signer = getSignatureAddress(
termsAndConditionsERC191,
signature
);
require(signer == msg.sender, "Invalid signature");
signedTermsAndConditions[msg.sender] = true;
}
/**
* @dev Allow incoming ETH transfers during the TGE period.
*/
function deposit(address referrer, bytes memory signature)
external
payable
notAborted
{
// Sign T&Cs if the signature is not empty.
// User must pass a valid signature before the first deposit.
if (signature.length != 0) signTermsAndConditions(signature);
// Assert that the user can deposit.
require(signedTermsAndConditions[msg.sender], "Must sign T&Cs");
require(hasTgeBeenStarted(), "TGE has not started yet");
require(!hasTgeEnded(), "TGE has finished");
uint256 currentDeposit = deposits[msg.sender];
// Revert if the user cap or TGE cap has already been met.
require(currentDeposit < userCap, "User cap met");
require(ethDeposited < depositCap, "TGE deposit cap met");
// Assert that the deposit amount is greater than zero.
uint256 deposit = msg.value;
assert(deposit > 0);
// Increase the depositorCount if first deposit by user.
if (currentDeposit == 0) depositorCount++;
if (currentDeposit + deposit > userCap) {
// Ensure deposit over user cap is returned.
safeSendEth(msg.sender, currentDeposit + deposit - userCap);
// Adjust user deposit.
deposit = userCap - currentDeposit;
} else if (ethDeposited + deposit > depositCap) {
// Ensure deposit over TGE cap is returned.
safeSendEth(msg.sender, ethDeposited + deposit - depositCap);
// Adjust user deposit.
deposit -= ethDeposited + deposit - depositCap;
}
// Only contribute to referrals if the hard cap hasn't been met yet.
uint256 hardCap = ethHardCap();
if (ethDeposited < hardCap) {
uint256 referralDepositAmount = deposit;
// Subtract surplus from hard cap if any.
if (ethDeposited + deposit > hardCap)
referralDepositAmount -= ethDeposited + deposit - hardCap;
referrerDeposits[referrer] += referralDepositAmount;
}
// Increase deposit variables.
ethDeposited += deposit;
deposits[msg.sender] += deposit;
}
/**
* @dev Claim depositor funds (FOREX and ETH) once the TGE has closed.
This may be called right after TGE closing for withdrawing surplus
ETH (if FOREX reached max price/hard cap) or once (again when) the
claim period starts for claiming both FOREX along with any surplus.
*/
function claim() external notAborted {
require(hasTgeEnded(), notClaimable);
(uint256 forex, uint256 forexReferred, uint256 eth) = balanceOf(
msg.sender
);
// Revert here if there's no ETH to withdraw as the FOREX claiming
// period may not have yet started.
require(eth > 0 || isTgeClaimable(), notClaimable);
forex += forexReferred;
// Claim forex only if the claimable period has started.
if (isTgeClaimable() && forex > 0) claimForex(forex);
// Claim ETH hardcap surplus if available.
if (eth > 0) claimEthSurplus(eth);
}
/**
* @dev Claims ETH for user.
* @param eth The amount of ETH to claim.
*/
function claimEthSurplus(uint256 eth) private {
if (claimedEth[msg.sender]) return;
claimedEth[msg.sender] = true;
if (eth > 0) safeSendEth(msg.sender, eth);
}
/**
* @dev Claims FOREX for user.
* @param forex The amount of FOREX to claim.
*/
function claimForex(uint256 forex) private {
if (claimedForex[msg.sender]) return;
claimedForex[msg.sender] = true;
IERC20(FOREX).safeTransfer(msg.sender, forex);
}
/**
* @dev Withdraws leftover forex in case the hard cap is not met during TGE.
*/
function withdrawRemainingForex(address recipient) external onlyOwner {
assert(!withdrawnRemainingForex);
// Revert if the TGE has not ended.
require(hasTgeEnded(), "TGE has not finished");
(uint256 forexClaimable, ) = getClaimableData();
uint256 remainingForex = forexAmount - forexClaimable;
withdrawnRemainingForex = true;
// Add address zero (null) referrals to withdrawal.
remainingForex += getReferralForexAmount(address(0));
if (remainingForex == 0) return;
IERC20(FOREX).safeTransfer(recipient, remainingForex);
}
/**
* @dev Returns an account's balance of claimable forex, referral forex,
and ETH.
* @param account The account to fetch the claimable balance for.
*/
function balanceOf(address account)
public
view
returns (
uint256 forex,
uint256 forexReferred,
uint256 eth
)
{
if (!hasTgeEnded()) return (0, 0, 0);
(uint256 forexClaimable, uint256 ethClaimable) = getClaimableData();
uint256 share = shareOf(account);
eth = claimedEth[account] ? 0 : (ethClaimable * share) / (1 ether);
if (claimedForex[account]) {
forex = 0;
forexReferred = 0;
} else {
forex = (forexClaimable * share) / (1 ether);
// Forex earned through referrals is 5% of the referred deposits
// in FOREX.
forexReferred = getReferralForexAmount(account);
}
}
/**
* @dev Returns an account's share over the TGE deposits.
* @param account The account to fetch the share for.
* @return Share value as an 18 decimal ratio. 1 ether = 100%.
*/
function shareOf(address account) public view returns (uint256) {
if (ethDeposited == 0) return 0;
return (deposits[account] * (1 ether)) / ethDeposited;
}
/**
* @dev Returns the ETH deposited by an address.
* @param depositor The depositor address.
*/
function getDeposit(address depositor) external view returns (uint256) {
return deposits[depositor];
}
/**
* @dev Whether the TGE already started. It could be closed even if
this function returns true.
*/
function hasTgeBeenStarted() private view returns (bool) {
return block.timestamp >= generationStartDate;
}
/**
* @dev Whether the TGE has ended and is closed for new deposits.
*/
function hasTgeEnded() private view returns (bool) {
return block.timestamp > generationStartDate + generationDuration;
}
/**
* @dev Whether the TGE funds can be claimed.
*/
function isTgeClaimable() private view returns (bool) {
return claimDate != 0 && block.timestamp >= claimDate;
}
/**
* @dev The amount of ETH required to generate all supply at max price.
*/
function ethHardCap() private view returns (uint256) {
return (forexAmount * maxTokenPrice) / (1 ether);
}
/**
* @dev Returns the forex price as established by the deposit amount.
* The formula for the price is the following:
* minPrice + ([maxPrice - minPrice] * min(deposit, maxDeposit)/maxDeposit)
* Where maxDeposit = ethHardCap()
*/
function forexPrice() public view returns (uint256) {
uint256 hardCap = ethHardCap();
uint256 depositTowardsHardCap = ethDeposited > hardCap
? hardCap
: ethDeposited;
uint256 priceRange = maxTokenPrice - minTokenPrice;
uint256 priceDelta = (priceRange * depositTowardsHardCap) / hardCap;
return minTokenPrice + priceDelta;
}
/**
* @dev Returns TGE data to be used for claims once the TGE closes.
*/
function getClaimableData()
private
view
returns (uint256 forexClaimable, uint256 ethClaimable)
{
assert(hasTgeEnded());
uint256 forexPrice = forexPrice();
uint256 hardCap = ethHardCap();
// ETH is only claimable if the deposits exceeded the hard cap.
ethClaimable = ethDeposited > hardCap ? ethDeposited - hardCap : 0;
// Forex is claimable up to the maximum supply -- when deposits match
// the hard cap amount.
forexClaimable =
((ethDeposited - ethClaimable) * (1 ether)) /
forexPrice;
}
/**
* @dev Returns the amount of FOREX earned by a referrer.
* @param referrer The referrer's address.
*/
function getReferralForexAmount(address referrer)
private
view
returns (uint256)
{
// Referral claims are disabled.
return 0;
}
/**
* @dev Aborts the TGE, stopping new deposits and withdrawing all funds
* for the owner.
* The only use case for this function is in the
* event of an emergency.
*/
function emergencyAbort() external onlyOwner {
assert(!aborted);
aborted = true;
emergencyWithdrawAllFunds();
}
/**
* @dev Withdraws all contract funds for the owner.
* The only use case for this function is in the
* event of an emergency.
*/
function emergencyWithdrawAllFunds() public onlyOwner {
// Transfer ETH.
uint256 balance = self.balance;
if (balance > 0) safeSendEth(msg.sender, balance);
// Transfer FOREX.
IERC20 forex = IERC20(FOREX);
balance = forex.balanceOf(self);
if (balance > 0) forex.transfer(msg.sender, balance);
}
/**
* @dev Withdraws all ETH funds for the owner.
* This function may be called at any time, as it correctly
* withdraws only the correct contribution amount, ignoring
* the ETH amount to be refunded if the deposits exceed
* the hard cap.
*/
function collectContributions() public onlyOwner {
uint256 hardCap = ethHardCap();
require(
ethWithdrawnByOwner < hardCap,
"Cannot withdraw more than hard cap amount"
);
uint256 amount = self.balance;
if (amount + ethWithdrawnByOwner > hardCap)
amount = hardCap - ethWithdrawnByOwner;
ethWithdrawnByOwner += amount;
require(amount > 0, "Nothing available for withdrawal");
safeSendEth(msg.sender, amount);
}
/**
* @dev Enables FOREX claiming from the next block.
* Requires the TGE to have been closed.
*/
function enableForexClaims() external onlyOwner {
assert(hasTgeEnded() && !isTgeClaimable());
claimDate = block.timestamp + 1;
}
/**
* @dev Sets the minimum and maximum token prices before the TGE starts.
* Also sets the deposit cap.
* @param min The minimum token price in ETH.
* @param max The maximum token price in ETH.
* @param _depositCap The ETH deposit cap.
*/
function setMinMaxForexPrices(
uint256 min,
uint256 max,
uint256 _depositCap
) external onlyOwner {
assert(!hasTgeBeenStarted());
require(max > min && _depositCap > max, "Invalid values");
minTokenPrice = min;
maxTokenPrice = max;
depositCap = _depositCap;
}
/**
* @dev Sends ETH and reverts if the transfer fails.
* @param recipient The transfer recipient.
* @param amount The transfer amount.
*/
function safeSendEth(address recipient, uint256 amount) private {
(bool success, ) = recipient.call{value: amount}("");
require(success, "Failed to send ETH");
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_setOwner(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
_setOwner(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");
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(
IERC20 token,
address spender,
uint256 value
) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
// Return data is optional
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;
abstract contract Signature {
/**
* @dev Returns the address that signed a message given a signature.
* @param message The message signed.
* @param signature The signature.
*/
function getSignatureAddress(bytes32 message, bytes memory signature)
internal
pure
returns (address)
{
assert(signature.length == 65);
uint8 v;
bytes32 r;
bytes32 s;
assembly {
// First 32 bytes after length prefix.
r := mload(add(signature, 32))
// Next 32 bytes.
s := mload(add(signature, 64))
// Final byte.
v := byte(0, mload(add(signature, 96)))
}
return ecrecover(message, v, r, s);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
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");
(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");
(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");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal 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
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}