Contract Name:
veFXSYieldDistributorV4
Contract Source Code:
File 1 of 1 : veFXSYieldDistributorV4
// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.8.0;
// Sources flattened with hardhat v2.6.7 https://hardhat.org
// File contracts/Math/Math.sol
/**
* @dev Standard math utilities missing in the Solidity language.
*/
library Math {
/**
* @dev Returns the largest of two numbers.
*/
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/
function average(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b) / 2 can overflow, so we distribute
return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
}
// babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
function sqrt(uint y) internal pure returns (uint z) {
if (y > 3) {
z = y;
uint x = y / 2 + 1;
while (x < z) {
z = x;
x = (y / x + x) / 2;
}
} else if (y != 0) {
z = 1;
}
}
}
// File contracts/Math/SafeMath.sol
/**
* @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.
*
* _Available since v2.4.0._
*/
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.
*
* _Available since v2.4.0._
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
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.
*
* _Available since v2.4.0._
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// File contracts/Curve/IveFXS.sol
pragma abicoder v2;
interface IveFXS {
struct LockedBalance {
int128 amount;
uint256 end;
}
function commit_transfer_ownership(address addr) external;
function apply_transfer_ownership() external;
function commit_smart_wallet_checker(address addr) external;
function apply_smart_wallet_checker() external;
function toggleEmergencyUnlock() external;
function recoverERC20(address token_addr, uint256 amount) external;
function get_last_user_slope(address addr) external view returns (int128);
function user_point_history__ts(address _addr, uint256 _idx) external view returns (uint256);
function locked__end(address _addr) external view returns (uint256);
function checkpoint() external;
function deposit_for(address _addr, uint256 _value) external;
function create_lock(uint256 _value, uint256 _unlock_time) external;
function increase_amount(uint256 _value) external;
function increase_unlock_time(uint256 _unlock_time) external;
function withdraw() external;
function balanceOf(address addr) external view returns (uint256);
function balanceOf(address addr, uint256 _t) external view returns (uint256);
function balanceOfAt(address addr, uint256 _block) external view returns (uint256);
function totalSupply() external view returns (uint256);
function totalSupply(uint256 t) external view returns (uint256);
function totalSupplyAt(uint256 _block) external view returns (uint256);
function totalFXSSupply() external view returns (uint256);
function totalFXSSupplyAt(uint256 _block) external view returns (uint256);
function changeController(address _newController) external;
function token() external view returns (address);
function supply() external view returns (uint256);
function locked(address addr) external view returns (LockedBalance memory);
function epoch() external view returns (uint256);
function point_history(uint256 arg0) external view returns (int128 bias, int128 slope, uint256 ts, uint256 blk, uint256 fxs_amt);
function user_point_history(address arg0, uint256 arg1) external view returns (int128 bias, int128 slope, uint256 ts, uint256 blk, uint256 fxs_amt);
function user_point_epoch(address arg0) external view returns (uint256);
function slope_changes(uint256 arg0) external view returns (int128);
function controller() external view returns (address);
function transfersEnabled() external view returns (bool);
function emergencyUnlockActive() external view returns (bool);
function name() external view returns (string memory);
function symbol() external view returns (string memory);
function version() external view returns (string memory);
function decimals() external view returns (uint256);
function future_smart_wallet_checker() external view returns (address);
function smart_wallet_checker() external view returns (address);
function admin() external view returns (address);
function future_admin() external view returns (address);
}
// File contracts/Uniswap/TransferHelper.sol
// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
function safeApprove(address token, address to, uint value) internal {
// bytes4(keccak256(bytes('approve(address,uint256)')));
(bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
}
function safeTransfer(address token, address to, uint value) internal {
// bytes4(keccak256(bytes('transfer(address,uint256)')));
(bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
}
function safeTransferFrom(address token, address from, address to, uint value) internal {
// bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
(bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
}
function safeTransferETH(address to, uint value) internal {
(bool success,) = to.call{value:value}(new bytes(0));
require(success, 'TransferHelper: ETH_TRANSFER_FAILED');
}
}
// File contracts/Common/Context.sol
/*
* @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 payable(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;
}
}
// File contracts/ERC20/IERC20.sol
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see {ERC20Detailed}.
*/
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);
}
// File contracts/Utils/Address.sol
/**
* @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);
}
/**
* @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");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(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);
}
}
}
}
// File contracts/ERC20/ERC20.sol
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20Mintable}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory __name, string memory __symbol) public {
_name = __name;
_symbol = __symbol;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.approve(address spender, uint256 amount)
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20};
*
* Requirements:
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from the caller.
*
* See {ERC20-_burn}.
*/
function burn(uint256 amount) public virtual {
_burn(_msgSender(), amount);
}
/**
* @dev Destroys `amount` tokens from `account`, deducting from the caller's
* allowance.
*
* See {ERC20-_burn} and {ERC20-allowance}.
*
* Requirements:
*
* - the caller must have allowance for `accounts`'s tokens of at least
* `amount`.
*/
function burnFrom(address account, uint256 amount) public virtual {
uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");
_approve(account, _msgSender(), decreasedAllowance);
_burn(account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
*
* This is internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
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);
}
/**
* @dev Destroys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See {_burn} and {_approve}.
*/
function _burnFrom(address account, uint256 amount) internal virtual {
_burn(account, amount);
_approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of `from`'s tokens
* will be to transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of `from`'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:using-hooks.adoc[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
// File contracts/ERC20/SafeERC20.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");
}
}
}
// File contracts/Utils/ReentrancyGuard.sol
/**
* @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].
*/
abstract contract ReentrancyGuard {
// 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.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor () internal {
_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.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_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;
}
}
// File contracts/Staking/Owned.sol
// https://docs.synthetix.io/contracts/Owned
contract Owned {
address public owner;
address public nominatedOwner;
constructor (address _owner) public {
require(_owner != address(0), "Owner address cannot be 0");
owner = _owner;
emit OwnerChanged(address(0), _owner);
}
function nominateNewOwner(address _owner) external onlyOwner {
nominatedOwner = _owner;
emit OwnerNominated(_owner);
}
function acceptOwnership() external {
require(msg.sender == nominatedOwner, "You must be nominated before you can accept ownership");
emit OwnerChanged(owner, nominatedOwner);
owner = nominatedOwner;
nominatedOwner = address(0);
}
modifier onlyOwner {
require(msg.sender == owner, "Only the contract owner may perform this action");
_;
}
event OwnerNominated(address newOwner);
event OwnerChanged(address oldOwner, address newOwner);
}
// File contracts/Staking/veFXSYieldDistributorV4.sol
// ====================================================================
// | ______ _______ |
// | / _____________ __ __ / ____(_____ ____ _____ ________ |
// | / /_ / ___/ __ `| |/_/ / /_ / / __ \/ __ `/ __ \/ ___/ _ \ |
// | / __/ / / / /_/ _> < / __/ / / / / / /_/ / / / / /__/ __/ |
// | /_/ /_/ \__,_/_/|_| /_/ /_/_/ /_/\__,_/_/ /_/\___/\___/ |
// | |
// ====================================================================
// ======================veFXSYieldDistributorV4=======================
// ====================================================================
// Distributes Frax protocol yield based on the claimer's veFXS balance
// V3: Yield will now not accrue for unlocked veFXS
// Frax Finance: https://github.com/FraxFinance
// Primary Author(s)
// Travis Moore: https://github.com/FortisFortuna
// Reviewer(s) / Contributor(s)
// Jason Huan: https://github.com/jasonhuan
// Sam Kazemian: https://github.com/samkazemian
// Originally inspired by Synthetix.io, but heavily modified by the Frax team (veFXS portion)
// https://github.com/Synthetixio/synthetix/blob/develop/contracts/StakingRewards.sol
contract veFXSYieldDistributorV4 is Owned, ReentrancyGuard {
using SafeMath for uint256;
using SafeERC20 for ERC20;
/* ========== STATE VARIABLES ========== */
// Instances
IveFXS private veFXS;
ERC20 public emittedToken;
// Addresses
address public emitted_token_address;
// Admin addresses
address public timelock_address;
// Constant for price precision
uint256 private constant PRICE_PRECISION = 1e6;
// Yield and period related
uint256 public periodFinish;
uint256 public lastUpdateTime;
uint256 public yieldRate;
uint256 public yieldDuration = 604800; // 7 * 86400 (7 days)
mapping(address => bool) public reward_notifiers;
// Yield tracking
uint256 public yieldPerVeFXSStored = 0;
mapping(address => uint256) public userYieldPerTokenPaid;
mapping(address => uint256) public yields;
// veFXS tracking
uint256 public totalVeFXSParticipating = 0;
uint256 public totalVeFXSSupplyStored = 0;
mapping(address => bool) public userIsInitialized;
mapping(address => uint256) public userVeFXSCheckpointed;
mapping(address => uint256) public userVeFXSEndpointCheckpointed;
mapping(address => uint256) private lastRewardClaimTime; // staker addr -> timestamp
// Greylists
mapping(address => bool) public greylist;
// Admin booleans for emergencies
bool public yieldCollectionPaused = false; // For emergencies
struct LockedBalance {
int128 amount;
uint256 end;
}
/* ========== MODIFIERS ========== */
modifier onlyByOwnGov() {
require( msg.sender == owner || msg.sender == timelock_address, "Not owner or timelock");
_;
}
modifier notYieldCollectionPaused() {
require(yieldCollectionPaused == false, "Yield collection is paused");
_;
}
modifier checkpointUser(address account) {
_checkpointUser(account);
_;
}
/* ========== CONSTRUCTOR ========== */
constructor (
address _owner,
address _emittedToken,
address _timelock_address,
address _veFXS_address
) Owned(_owner) {
emitted_token_address = _emittedToken;
emittedToken = ERC20(_emittedToken);
veFXS = IveFXS(_veFXS_address);
lastUpdateTime = block.timestamp;
timelock_address = _timelock_address;
reward_notifiers[_owner] = true;
}
/* ========== VIEWS ========== */
function fractionParticipating() external view returns (uint256) {
return totalVeFXSParticipating.mul(PRICE_PRECISION).div(totalVeFXSSupplyStored);
}
// Only positions with locked veFXS can accrue yield. Otherwise, expired-locked veFXS
// is de-facto rewards for FXS.
function eligibleCurrentVeFXS(address account) public view returns (uint256 eligible_vefxs_bal, uint256 stored_ending_timestamp) {
uint256 curr_vefxs_bal = veFXS.balanceOf(account);
// Stored is used to prevent abuse
stored_ending_timestamp = userVeFXSEndpointCheckpointed[account];
// Only unexpired veFXS should be eligible
if (stored_ending_timestamp != 0 && (block.timestamp >= stored_ending_timestamp)){
eligible_vefxs_bal = 0;
}
else if (block.timestamp >= stored_ending_timestamp){
eligible_vefxs_bal = 0;
}
else {
eligible_vefxs_bal = curr_vefxs_bal;
}
}
function lastTimeYieldApplicable() public view returns (uint256) {
return Math.min(block.timestamp, periodFinish);
}
function yieldPerVeFXS() public view returns (uint256) {
if (totalVeFXSSupplyStored == 0) {
return yieldPerVeFXSStored;
} else {
return (
yieldPerVeFXSStored.add(
lastTimeYieldApplicable()
.sub(lastUpdateTime)
.mul(yieldRate)
.mul(1e18)
.div(totalVeFXSSupplyStored)
)
);
}
}
function earned(address account) public view returns (uint256) {
// Uninitialized users should not earn anything yet
if (!userIsInitialized[account]) return 0;
// Get eligible veFXS balances
(uint256 eligible_current_vefxs, uint256 ending_timestamp) = eligibleCurrentVeFXS(account);
// If your veFXS is unlocked
uint256 eligible_time_fraction = PRICE_PRECISION;
if (eligible_current_vefxs == 0){
// And you already claimed after expiration
if (lastRewardClaimTime[account] >= ending_timestamp) {
// You get NOTHING. You LOSE. Good DAY ser!
return 0;
}
// You haven't claimed yet
else {
uint256 eligible_time = (ending_timestamp).sub(lastRewardClaimTime[account]);
uint256 total_time = (block.timestamp).sub(lastRewardClaimTime[account]);
eligible_time_fraction = PRICE_PRECISION.mul(eligible_time).div(total_time);
}
}
// If the amount of veFXS increased, only pay off based on the old balance
// Otherwise, take the midpoint
uint256 vefxs_balance_to_use;
{
uint256 old_vefxs_balance = userVeFXSCheckpointed[account];
if (eligible_current_vefxs > old_vefxs_balance){
vefxs_balance_to_use = old_vefxs_balance;
}
else {
vefxs_balance_to_use = ((eligible_current_vefxs).add(old_vefxs_balance)).div(2);
}
}
return (
vefxs_balance_to_use
.mul(yieldPerVeFXS().sub(userYieldPerTokenPaid[account]))
.mul(eligible_time_fraction)
.div(1e18 * PRICE_PRECISION)
.add(yields[account])
);
}
function getYieldForDuration() external view returns (uint256) {
return (yieldRate.mul(yieldDuration));
}
/* ========== MUTATIVE FUNCTIONS ========== */
function _checkpointUser(address account) internal {
// Need to retro-adjust some things if the period hasn't been renewed, then start a new one
sync();
// Calculate the earnings first
_syncEarned(account);
// Get the old and the new veFXS balances
uint256 old_vefxs_balance = userVeFXSCheckpointed[account];
uint256 new_vefxs_balance = veFXS.balanceOf(account);
// Update the user's stored veFXS balance
userVeFXSCheckpointed[account] = new_vefxs_balance;
// Update the user's stored ending timestamp
IveFXS.LockedBalance memory curr_locked_bal_pack = veFXS.locked(account);
userVeFXSEndpointCheckpointed[account] = curr_locked_bal_pack.end;
// Update the total amount participating
if (new_vefxs_balance >= old_vefxs_balance) {
uint256 weight_diff = new_vefxs_balance.sub(old_vefxs_balance);
totalVeFXSParticipating = totalVeFXSParticipating.add(weight_diff);
} else {
uint256 weight_diff = old_vefxs_balance.sub(new_vefxs_balance);
totalVeFXSParticipating = totalVeFXSParticipating.sub(weight_diff);
}
// Mark the user as initialized
if (!userIsInitialized[account]) {
userIsInitialized[account] = true;
lastRewardClaimTime[account] = block.timestamp;
}
}
function _syncEarned(address account) internal {
if (account != address(0)) {
uint256 earned0 = earned(account);
yields[account] = earned0;
userYieldPerTokenPaid[account] = yieldPerVeFXSStored;
}
}
// Anyone can checkpoint another user
function checkpointOtherUser(address user_addr) external {
_checkpointUser(user_addr);
}
// Checkpoints the user
function checkpoint() external {
_checkpointUser(msg.sender);
}
function getYield() external nonReentrant notYieldCollectionPaused checkpointUser(msg.sender) returns (uint256 yield0) {
require(greylist[msg.sender] == false, "Address has been greylisted");
yield0 = yields[msg.sender];
if (yield0 > 0) {
yields[msg.sender] = 0;
TransferHelper.safeTransfer(
emitted_token_address,
msg.sender,
yield0
);
emit YieldCollected(msg.sender, yield0, emitted_token_address);
}
lastRewardClaimTime[msg.sender] = block.timestamp;
}
function sync() public {
// Update the total veFXS supply
yieldPerVeFXSStored = yieldPerVeFXS();
totalVeFXSSupplyStored = veFXS.totalSupply();
lastUpdateTime = lastTimeYieldApplicable();
}
function notifyRewardAmount(uint256 amount) external {
// Only whitelisted addresses can notify rewards
require(reward_notifiers[msg.sender], "Sender not whitelisted");
// Handle the transfer of emission tokens via `transferFrom` to reduce the number
// of transactions required and ensure correctness of the smission amount
emittedToken.safeTransferFrom(msg.sender, address(this), amount);
// Update some values beforehand
sync();
// Update the new yieldRate
if (block.timestamp >= periodFinish) {
yieldRate = amount.div(yieldDuration);
} else {
uint256 remaining = periodFinish.sub(block.timestamp);
uint256 leftover = remaining.mul(yieldRate);
yieldRate = amount.add(leftover).div(yieldDuration);
}
// Update duration-related info
lastUpdateTime = block.timestamp;
periodFinish = block.timestamp.add(yieldDuration);
emit RewardAdded(amount, yieldRate);
}
/* ========== RESTRICTED FUNCTIONS ========== */
// Added to support recovering LP Yield and other mistaken tokens from other systems to be distributed to holders
function recoverERC20(address tokenAddress, uint256 tokenAmount) external onlyByOwnGov {
// Only the owner address can ever receive the recovery withdrawal
TransferHelper.safeTransfer(tokenAddress, owner, tokenAmount);
emit RecoveredERC20(tokenAddress, tokenAmount);
}
function setYieldDuration(uint256 _yieldDuration) external onlyByOwnGov {
require( periodFinish == 0 || block.timestamp > periodFinish, "Previous yield period must be complete before changing the duration for the new period");
yieldDuration = _yieldDuration;
emit YieldDurationUpdated(yieldDuration);
}
function greylistAddress(address _address) external onlyByOwnGov {
greylist[_address] = !(greylist[_address]);
}
function toggleRewardNotifier(address notifier_addr) external onlyByOwnGov {
reward_notifiers[notifier_addr] = !reward_notifiers[notifier_addr];
}
function setPauses(bool _yieldCollectionPaused) external onlyByOwnGov {
yieldCollectionPaused = _yieldCollectionPaused;
}
function setYieldRate(uint256 _new_rate0, bool sync_too) external onlyByOwnGov {
yieldRate = _new_rate0;
if (sync_too) {
sync();
}
}
function setTimelock(address _new_timelock) external onlyByOwnGov {
timelock_address = _new_timelock;
}
/* ========== EVENTS ========== */
event RewardAdded(uint256 reward, uint256 yieldRate);
event OldYieldCollected(address indexed user, uint256 yield, address token_address);
event YieldCollected(address indexed user, uint256 yield, address token_address);
event YieldDurationUpdated(uint256 newDuration);
event RecoveredERC20(address token, uint256 amount);
event YieldPeriodRenewed(address token, uint256 yieldRate);
event DefaultInitialization();
/* ========== A CHICKEN ========== */
//
// ,~.
// ,-'__ `-,
// {,-' `. } ,')
// ,( a ) `-.__ ,',')~,
// <=.) ( `-.__,==' ' ' '}
// ( ) /)
// `-'\ , )
// | \ `~. /
// \ `._ \ /
// \ `._____,' ,'
// `-. ,'
// `-._ _,-'
// 77jj'
// //_||
// __//--'/`
// ,--'/` '
//
// [hjw] https://textart.io/art/vw6Sa3iwqIRGkZsN1BC2vweF/chicken
}
