CrowdFi V1 Source
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "@openzeppelin-upgradeable/contracts/proxy/utils/Initializable.sol";
import "@openzeppelin-upgradeable/contracts/security/ReentrancyGuardUpgradeable.sol";
/**
*
* Each instance of a Crowdfinancing Contract represents a single campaign with a goal
* of raising funds for a specific purpose. The contract is deployed by the creator through
* the CrowdFinancingV1Factory contract. The creator specifies the recipient address, the
* token to use for payments, the minimum and maximum funding goals, the minimum and maximum
* contribution amounts, and the start and end times.
*
* The campaign is deemed successful if the minimum funding goal is met by the end time, or the
* maximum funding goal is met before the end time.
*
* If the campaign is successful funds can be transferred to the recipient address. If the
* campaign is not successful the funds can be withdrawn by the contributors.
*
* @title Crowd Financing with Optional Yield
* @author Fabric Inc.
*
*/
contract CrowdFinancingV1 is Initializable, ReentrancyGuardUpgradeable, IERC20 {
/// @dev Guard to gate ERC20 specific functions
modifier erc20Only() {
require(_erc20, "erc20 only fn called");
_;
}
/// @dev Guard to gate ETH specific functions
modifier ethOnly() {
require(!_erc20, "ETH only fn called");
_;
}
/// @dev Guard to ensure yields are allowed
modifier yieldGuard(uint256 amount) {
require(_state == State.FUNDED, "Cannot accept payment");
require(amount > 0, "Amount is 0");
_;
}
/// @dev Guard to ensure contributions are allowed
modifier contributionGuard(uint256 amount) {
require(isContributionAllowed(), "Contributions are not allowed");
uint256 total = _contributions[msg.sender] + amount;
require(total >= _minContribution, "Contribution amount is too low");
require(total <= _maxContribution, "Contribution amount is too high");
require(_contributionTotal + amount <= _goalMax, "Contribution amount exceeds max goal");
_;
}
/// @dev If transfer doesn't occur within the TRANSFER_WINDOW, the campaign can be unlocked
/// and put into a failed state for withdraws. This is to prevent a campaign from being
/// locked forever if the recipient addresses are compromised.
uint256 private constant TRANSFER_WINDOW = 90 days;
/// @dev Max campaign duration: 90 Days
uint256 private constant MAX_DURATION_SECONDS = 90 days;
/// @dev Min campaign duration: 30 minutes
uint256 private constant MIN_DURATION_SECONDS = 30 minutes;
/// @dev Allow a campaign to be deployed where the start time is up to one minute in the past
uint256 private constant PAST_START_TOLERANCE_SECONDS = 60;
/// @dev Maximum fee basis points (12.5%)
uint16 private constant MAX_FEE_BIPS = 1250;
/// @dev Maximum basis points
uint16 private constant MAX_BIPS = 10_000;
/// @dev Emitted when an account contributes funds to the contract
event Contribution(address indexed account, uint256 numTokens);
/// @dev Emitted when an account withdraws their initial contribution or yield balance
event Withdraw(address indexed account, uint256 numTokens);
/// @dev Emitted when the funds are transferred to the recipient and when
/// fees are transferred to the fee collector, if specified
event TransferContributions(address indexed account, uint256 numTokens);
/// @dev Emitted when the campaign is marked as failed
event Fail();
/// @dev Emitted when yieldEth or yieldERC20 are called
event Payout(address indexed account, uint256 numTokens);
/// @dev A state enum to track the current state of the campaign
enum State {
FUNDING,
FAILED,
FUNDED
}
/// @dev The current state of the contract
State private _state;
/// @dev The address of the recipient in the event of a successful campaign
address private _recipientAddress;
/// @dev The token used for funding (optional)
IERC20 private _token;
/// @dev The minimum funding goal to meet for a successful campaign
uint256 private _goalMin;
/// @dev The maximum funding goal. If this goal is met, funds can be transferred early
uint256 private _goalMax;
/// @dev The minimum tokens an account can contribute
uint256 private _minContribution;
/// @dev The maximum tokens an account can contribute
uint256 private _maxContribution;
/// @dev The start timestamp for the campaign
uint256 private _startTimestamp;
/// @dev The end timestamp for the campaign
uint256 private _endTimestamp;
/// @dev The total amount contributed by all accounts
uint256 private _contributionTotal;
/// @dev The total amount withdrawn by all accounts
uint256 private _withdrawTotal;
/// @dev The mapping from account to balance (contributions or transfers)
mapping(address => uint256) private _contributions;
/// @dev The mapping from account to withdraws
mapping(address => uint256) private _withdraws;
/// @dev ERC20 allowances
mapping(address => mapping(address => uint256)) private _allowances;
// Fee related items
/// @dev The optional address of the fee recipient
address private _feeRecipient;
/// @dev The transfer fee in basis points, sent to the fee recipient upon transfer
uint16 private _feeTransferBips;
/// @dev The yield fee in basis points, used to dilute the cap table upon transfer
uint16 private _feeYieldBips;
/// @dev Track the number of tokens sent via yield calls
uint256 private _yieldTotal;
/// @dev Flag indicating the contract works with ERC20 tokens rather than ETH
bool private _erc20;
/// @dev This contract is intended for use with proxies, so we prevent direct
/// initialization. This contract will fail to function properly without a proxy
constructor() {
_disableInitializers();
}
/**
* @dev Initialize acts as the constructor, as this contract is intended to work with proxy contracts.
*
* @param recipient the address of the recipient, where funds are transferred when conditions are met
* @param minGoal the minimum funding goal for the financing round
* @param maxGoal the maximum funding goal for the financing round
* @param minContribution the minimum initial contribution an account can make
* @param maxContribution the maximum contribution an account can make
* @param startTimestamp the UNIX time in seconds denoting when contributions can start
* @param endTimestamp the UNIX time in seconds denoting when contributions are no longer allowed
* @param erc20TokenAddr the address of the ERC20 token used for funding, or the 0 address for native token (ETH)
* @param feeRecipientAddr the address of the fee recipient, or the 0 address if no fees are collected
* @param feeTransferBips the transfer fee in basis points, collected during the transfer call
* @param feeYieldBips the yield fee in basis points. Dilutes the cap table for the fee recipient.
*/
function initialize(
address recipient,
uint256 minGoal,
uint256 maxGoal,
uint256 minContribution,
uint256 maxContribution,
uint256 startTimestamp,
uint256 endTimestamp,
address erc20TokenAddr,
address feeRecipientAddr,
uint16 feeTransferBips,
uint16 feeYieldBips
) external initializer {
require(recipient != address(0), "Invalid recipient address");
require(startTimestamp + PAST_START_TOLERANCE_SECONDS >= block.timestamp, "Invalid start time");
require(startTimestamp + MIN_DURATION_SECONDS <= endTimestamp, "Invalid time range");
require(
endTimestamp > block.timestamp && (endTimestamp - startTimestamp) < MAX_DURATION_SECONDS, "Invalid end time"
);
require(minGoal > 0, "Min goal must be > 0");
require(minGoal <= maxGoal, "Min goal must be <= Max goal");
require(minContribution > 0, "Min contribution must be > 0");
require(minContribution <= maxContribution, "Min contribution must be <= Max contribution");
require(
minContribution < (maxGoal - minGoal) || minContribution == 1,
"Min contribution must be < (maxGoal - minGoal) or 1"
);
require(feeTransferBips <= MAX_FEE_BIPS, "Transfer fee too high");
require(feeYieldBips <= MAX_FEE_BIPS, "Yield fee too high");
if (feeRecipientAddr != address(0)) {
require(feeTransferBips > 0 || feeYieldBips > 0, "Fees required when fee recipient is present");
} else {
require(feeTransferBips == 0 && feeYieldBips == 0, "Fees must be 0 when there is no fee recipient");
}
_recipientAddress = recipient;
_goalMin = minGoal;
_goalMax = maxGoal;
_minContribution = minContribution;
_maxContribution = maxContribution;
_startTimestamp = startTimestamp;
_endTimestamp = endTimestamp;
_token = IERC20(erc20TokenAddr);
_erc20 = erc20TokenAddr != address(0);
_feeRecipient = feeRecipientAddr;
_feeTransferBips = feeTransferBips;
_feeYieldBips = feeYieldBips;
_contributionTotal = 0;
_withdrawTotal = 0;
_state = State.FUNDING;
__ReentrancyGuard_init();
}
///////////////////////////////////////////
// Contributions
///////////////////////////////////////////
/**
* @notice Contribute ERC20 tokens into the contract
*
* #### Events
* - Emits a {Contribution} event
* - Emits a {Transfer} event (ERC20)
*
* #### Requirements
* - `amount` must be within range of min and max contribution for account
* - `amount` must not cause max goal to be exceeded
* - `amount` must be approved for transfer by the caller
* - contributions must be allowed
* - the contract must be configured to work with ERC20 tokens
*
* @param amount the amount of ERC20 tokens to contribute
*
*/
function contributeERC20(uint256 amount) external erc20Only nonReentrant {
_addContribution(msg.sender, _transferSafe(msg.sender, amount));
}
/**
* @notice Contribute ETH into the contract
*
* #### Events
* - Emits a {Contribution} event
* - Emits a {Transfer} event (ERC20)
*
* #### Requirements
* - `msg.value` must be within range of min and max contribution for account
* - `msg.value` must not cause max goal to be exceeded
* - contributions must be allowed
* - the contract must be configured to work with ETH
*/
function contributeEth() external payable ethOnly {
_addContribution(msg.sender, msg.value);
}
/**
* @dev Add a contribution to the account and update totals
*
* @param account the account to add the contribution to
* @param amount the amount of the contribution
*/
function _addContribution(address account, uint256 amount) private contributionGuard(amount) {
_contributions[account] += amount;
_contributionTotal += amount;
emit Contribution(account, amount);
emit Transfer(address(0), account, amount);
}
/**
* @return true if contributions are allowed
*/
function isContributionAllowed() public view returns (bool) {
return _state == State.FUNDING && !isGoalMaxMet() && isStarted() && !isEnded();
}
///////////////////////////////////////////
// Transfer
///////////////////////////////////////////
/**
* @return true if the goal was met and funds can be transferred
*/
function isTransferAllowed() public view returns (bool) {
return ((isEnded() && isGoalMinMet()) || isGoalMaxMet()) && _state == State.FUNDING;
}
/**
* @notice Transfer funds to the recipient and change the state
*
* #### Events
* Emits a {TransferContributions} event if the target was met and funds transferred
*/
function transferBalanceToRecipient() external {
require(isTransferAllowed(), "Transfer not allowed");
_state = State.FUNDED;
uint256 feeAmount = _calculateTransferFee();
uint256 transferAmount = _contributionTotal - feeAmount;
// This can mutate _contributionTotal, so that withdraws don't over withdraw
_allocateYieldFee();
// If any transfer fee is present, pay that out to the fee recipient
if (feeAmount > 0) {
emit TransferContributions(_feeRecipient, feeAmount);
if (_erc20) {
SafeERC20.safeTransfer(_token, _feeRecipient, feeAmount);
} else {
(bool sent,) = payable(_feeRecipient).call{value: feeAmount}("");
require(sent, "Failed to transfer Ether");
}
}
emit TransferContributions(_recipientAddress, transferAmount);
if (_erc20) {
SafeERC20.safeTransfer(_token, _recipientAddress, transferAmount);
} else {
(bool sent,) = payable(_recipientAddress).call{value: transferAmount}("");
require(sent, "Failed to transfer Ether");
}
}
/**
* @dev Dilutes supply by allocating tokens to the fee collector, allowing for
* withdraws of yield
*/
function _allocateYieldFee() private returns (uint256) {
if (_feeYieldBips == 0) {
return 0;
}
uint256 feeAllocation = ((_contributionTotal * _feeYieldBips) / (MAX_BIPS - _feeYieldBips));
_contributions[_feeRecipient] += feeAllocation;
_contributionTotal += feeAllocation;
return feeAllocation;
}
/**
* @dev Calculates a fee to transfer to the fee collector
*/
function _calculateTransferFee() private view returns (uint256) {
if (_feeTransferBips == 0) {
return 0;
}
return (_contributionTotal * _feeTransferBips) / (MAX_BIPS);
}
/**
* @return true if the minimum goal was met
*/
function isGoalMinMet() public view returns (bool) {
return _contributionTotal >= _goalMin;
}
/**
* @return true if the maximum goal was met
*/
function isGoalMaxMet() public view returns (bool) {
return _contributionTotal >= _goalMax;
}
///////////////////////////////////////////
// Unlocking Funds After Failed Transfer
///////////////////////////////////////////
/**
* @notice In the event that a transfer fails due to recipient contract behavior, the campaign
* can be unlocked (marked as failed) to allow contributors to withdraw their funds. This can only
* occur if the state of the campaign is FUNDING and the transfer window
* has expired. Note: Recipient should invoke transferBalanceToRecipient immediately upon success
* to prevent this function from being callable. This is a safety mechanism to prevent
* permanent loss of funds.
*
* #### Events
* - Emits {Fail} event
*/
function unlockFailedFunds() external {
require(isUnlockAllowed(), "Funds cannot be unlocked");
_state = State.FAILED;
emit Fail();
}
///////////////////////////////////////////
// Phase 3: Yield / Refunds / Withdraws
///////////////////////////////////////////
/**
* @notice Yield ERC20 tokens to all campaign token holders in proportion to their token balance
*
* #### Requirements
* - `amount` must be greater than 0
* - `amount` must be approved for transfer for the contract
*
* #### Events
* - Emits {Payout} event with amount = `amount`
*
* @param amount the amount of tokens to payout
*/
function yieldERC20(uint256 amount) external erc20Only yieldGuard(amount) nonReentrant {
_trackYield(msg.sender, _transferSafe(msg.sender, amount));
}
/**
* @notice Yield ETH to all token holders in proportion to their balance
*
* #### Requirements
* - `msg.value` must be greater than 0
*
* #### Events
* - Emits {Payout} event with amount = `msg.value`
*/
function yieldEth() external payable ethOnly yieldGuard(msg.value) nonReentrant {
_trackYield(msg.sender, msg.value);
}
/**
* @dev Emit a Payout event and increase yield total
*/
function _trackYield(address from, uint256 amount) private {
emit Payout(from, amount);
_yieldTotal += amount;
}
/**
* @return The total amount of tokens/wei paid back by the recipient
*/
function yieldTotal() public view returns (uint256) {
return _yieldTotal;
}
/**
* @param account the address of a contributor or token holder
*
* @return The total tokens withdrawn for a given account
*/
function withdrawsOf(address account) public view returns (uint256) {
return _withdraws[account];
}
/**
* @return true if the contract allows withdraws
*/
function isWithdrawAllowed() public view returns (bool) {
return state() == State.FUNDED || state() == State.FAILED || (isEnded() && !isGoalMinMet());
}
/**
* @return The total amount of tokens paid back to a given contributor
*/
function _payoutsMadeTo(address account) private view returns (uint256) {
if (_contributionTotal == 0) {
return 0;
}
return (_contributions[account] * yieldTotal()) / _contributionTotal;
}
/**
* @param account the address of a token holder
*
* @return The withdrawable amount of tokens for a given account, attributable to yield
*/
function yieldBalanceOf(address account) public view returns (uint256) {
return _payoutsMadeTo(account) - withdrawsOf(account);
}
/**
* @param account the address of a contributor
*
* @return The total amount of tokens earned by the given account through yield
*/
function yieldTotalOf(address account) public view returns (uint256) {
uint256 _payout = _payoutsMadeTo(account);
if (_payout <= _contributions[account]) {
return 0;
}
return _payout - _contributions[account];
}
/**
* @notice Withdraw all available funds to the caller if withdraws are allowed and
* the caller has a contribution balance (campaign failed), or a yield balance (campaign succeeded)
*
* #### Events
* - Emits a {Withdraw} event with amount = the amount withdrawn
* - Emits a {Transfer} event representing a token burn if the campaign failed
*/
function withdraw() external {
require(isWithdrawAllowed(), "Withdraw not allowed");
// Set the state to failed
if (_state == State.FUNDING) {
_state = State.FAILED;
emit Fail();
}
address account = msg.sender;
if (_state == State.FUNDED) {
_withdrawYieldBalance(account);
} else {
_withdrawContribution(account);
}
}
/**
* @dev Withdraw the initial contribution for the given account
*/
function _withdrawContribution(address account) private {
uint256 amount = _contributions[account];
require(amount > 0, "No balance");
_contributions[account] = 0;
_contributionTotal -= amount;
emit Withdraw(account, amount);
emit Transfer(account, address(0), amount);
if (_erc20) {
SafeERC20.safeTransfer(_token, account, amount);
} else {
(bool sent,) = payable(account).call{value: amount}("");
require(sent, "Failed to transfer Ether");
}
}
/**
* @dev Withdraw the available yield balance for the given account
*/
function _withdrawYieldBalance(address account) private {
uint256 amount = yieldBalanceOf(account);
require(amount > 0, "No balance");
_withdraws[account] += amount;
_withdrawTotal += amount;
emit Withdraw(account, amount);
if (_erc20) {
SafeERC20.safeTransfer(_token, account, amount);
} else {
(bool sent,) = payable(account).call{value: amount}("");
require(sent, "Failed to transfer Ether");
}
}
///////////////////////////////////////////
// Utility Functions
///////////////////////////////////////////
/**
* @dev Token transfer function which leverages allowance. Additionally, it accounts
* for tokens which take fees on transfer. Fetch the balance of this contract
* before and after transfer, to determine the real amount of tokens transferred.
*
* @notice this contract is not compatible with tokens that rebase
*
* @return The amount of tokens transferred after fees
*/
function _transferSafe(address account, uint256 amount) private returns (uint256) {
uint256 allowed = _token.allowance(msg.sender, address(this));
require(amount <= allowed, "Amount exceeds token allowance");
uint256 priorBalance = _token.balanceOf(address(this));
SafeERC20.safeTransferFrom(_token, account, address(this), amount);
uint256 postBalance = _token.balanceOf(address(this));
return postBalance - priorBalance;
}
///////////////////////////////////////////
// IERC20 Implementation
///////////////////////////////////////////
/**
* @inheritdoc IERC20
* @dev Contributions mint tokens and increase the total supply
*/
function totalSupply() external view returns (uint256) {
return _contributionTotal;
}
/// @inheritdoc IERC20
function balanceOf(address account) external view returns (uint256) {
return _contributions[account];
}
/// @inheritdoc IERC20
function transfer(address to, uint256 amount) external returns (bool) {
_transfer(msg.sender, to, amount);
return true;
}
/**
* See ERC20._transfer
* @dev The primary difference here is that we also need to adjust withdraws
* to prevent over-withdrawal of yield/contribution
*/
function _transfer(address from, address to, uint256 amount) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
uint256 fromBalance = _contributions[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_contributions[from] = fromBalance - amount;
// Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
// decrementing then incrementing.
_contributions[to] += amount;
}
// Transfer partial withdraws to balance payouts
if (_state == State.FUNDED) {
uint256 fromWithdraws = _withdraws[from];
uint256 withdrawAmount = (amount * fromWithdraws) / fromBalance;
unchecked {
_withdraws[from] = fromWithdraws - withdrawAmount;
_withdraws[to] += withdrawAmount;
}
}
emit Transfer(from, to, amount);
}
/// @inheritdoc IERC20
function allowance(address owner, address spender) public view returns (uint256) {
return _allowances[owner][spender];
}
/// @inheritdoc IERC20
function approve(address spender, uint256 amount) external returns (bool) {
_approve(msg.sender, spender, amount);
return true;
}
/// See ERC20._spendAllowance
function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}
/// See ERC20._approve
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/// @inheritdoc IERC20
function transferFrom(address from, address to, uint256 amount) external returns (bool) {
address spender = msg.sender;
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
return true;
}
/// See ERC20.increaseAllowance
function increaseAllowance(address spender, uint256 addedValue) external virtual returns (bool) {
address owner = msg.sender;
_approve(owner, spender, allowance(owner, spender) + addedValue);
return true;
}
/// See ERC20.decreaseAllowance
function decreaseAllowance(address spender, uint256 subtractedValue) external virtual returns (bool) {
address owner = msg.sender;
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
///////////////////////////////////////////
// Public/External Views
///////////////////////////////////////////
/**
* @dev The values can be 0, indicating the account is not allowed to contribute.
* This method is helpful for preflight checks to ensure the amount is within the range.
*
* @return min The minimum contribution for the account
* @return max The maximum contribution for the account
*/
function contributionRangeFor(address account) external view returns (uint256 min, uint256 max) {
uint256 balance = _contributions[account];
if (balance >= _maxContribution || isGoalMaxMet()) {
return (0, 0);
}
int256 minContribution = int256(_minContribution) - int256(balance);
if (minContribution <= 0) {
minContribution = 1;
}
uint256 remainingGoal = _goalMax - _contributionTotal;
// If the remaining goal is less than the minimum contribution, then the account cannot contribute
// This can lead to a gap between the supply and max goal, but existing contributors can top it off if
// they are anxious to transfer early
if (remainingGoal < uint256(minContribution)) {
return (0, 0);
}
return (uint256(minContribution), Math.min(_maxContribution - balance, remainingGoal));
}
/**
* @return The current state of the campaign
*/
function state() public view returns (State) {
return _state;
}
/**
* @return The minimum allowed contribution of ERC20 tokens or WEI
*/
function minAllowedContribution() external view returns (uint256) {
return _minContribution;
}
/**
* @return The maximum allowed contribution of ERC20 tokens or WEI
*/
function maxAllowedContribution() external view returns (uint256) {
return _maxContribution;
}
/**
* @return The unix timestamp in seconds when the time window for contribution starts
*/
function startsAt() external view returns (uint256) {
return _startTimestamp;
}
/**
* @return true if the time window for contribution has started
*/
function isStarted() public view returns (bool) {
return block.timestamp >= _startTimestamp;
}
/**
* @return The unix timestamp in seconds when the contribution window ends
*/
function endsAt() external view returns (uint256) {
return _endTimestamp;
}
/**
* @return true if the time window for contribution has closed
*/
function isEnded() public view returns (bool) {
return block.timestamp >= _endTimestamp;
}
/**
* @return The address of the recipient
*/
function recipientAddress() external view returns (address) {
return _recipientAddress;
}
/**
* @return true if the contract is ETH denominated
*/
function isEthDenominated() public view returns (bool) {
return !_erc20;
}
/**
* @return The address of the ERC20 Token, or 0x0 if ETH
*/
function erc20Address() external view returns (address) {
return address(_token);
}
/**
* @return The minimum goal amount as ERC20 tokens or WEI
*/
function goalMin() external view returns (uint256) {
return _goalMin;
}
/**
* @return The maximum goal amount as ERC20 tokens or WEI
*/
function goalMax() external view returns (uint256) {
return _goalMax;
}
/**
* @return The transfer fee as basis points
*/
function transferFeeBips() external view returns (uint16) {
return _feeTransferBips;
}
/**
* @return The yield fee as basis points
*/
function yieldFeeBips() external view returns (uint16) {
return _feeYieldBips;
}
/**
* @return The address where the fees are transferred to, or 0x0 if no fees are collected
*/
function feeRecipientAddress() external view returns (address) {
return _feeRecipient;
}
/**
* @return true if the funds are unlockable, which means the campaign succeeded, but transfer
* failed to occur within the transfer window
*/
function isUnlockAllowed() public view returns (bool) {
return _state == State.FUNDING && block.timestamp >= _endTimestamp + TRANSFER_WINDOW;
}
}