Contract Name:
FraxlendPair
Contract Source Code:
// SPDX-License-Identifier: ISC
pragma solidity ^0.8.16;
// ====================================================================
// | ______ _______ |
// | / _____________ __ __ / ____(_____ ____ _____ ________ |
// | / /_ / ___/ __ `| |/_/ / /_ / / __ \/ __ `/ __ \/ ___/ _ \ |
// | / __/ / / / /_/ _> < / __/ / / / / / /_/ / / / / /__/ __/ |
// | /_/ /_/ \__,_/_/|_| /_/ /_/_/ /_/\__,_/_/ /_/\___/\___/ |
// | |
// ====================================================================
// ========================== FraxlendPair ============================
// ====================================================================
// Frax Finance: https://github.com/FraxFinance
// Primary Author
// Drake Evans: https://github.com/DrakeEvans
// Reviewers
// Dennis: https://github.com/denett
// Sam Kazemian: https://github.com/samkazemian
// Travis Moore: https://github.com/FortisFortuna
// Jack Corddry: https://github.com/corddry
// Rich Gee: https://github.com/zer0blockchain
// ====================================================================
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
import "./FraxlendPairConstants.sol";
import "./FraxlendPairCore.sol";
import "./libraries/VaultAccount.sol";
import "./libraries/SafeERC20.sol";
import "./interfaces/IERC4626.sol";
import "./interfaces/IFraxlendWhitelist.sol";
import "./interfaces/IRateCalculator.sol";
import "./interfaces/ISwapper.sol";
contract FraxlendPair is IERC20Metadata, FraxlendPairCore {
using VaultAccountingLibrary for VaultAccount;
using SafeERC20 for IERC20;
constructor(
bytes memory _configData,
bytes memory _immutables,
uint256 _maxLTV,
uint256 _liquidationFee,
uint256 _maturityDate,
uint256 _penaltyRate,
bool _isBorrowerWhitelistActive,
bool _isLenderWhitelistActive
)
FraxlendPairCore(
_configData,
_immutables,
_maxLTV,
_liquidationFee,
_maturityDate,
_penaltyRate,
_isBorrowerWhitelistActive,
_isLenderWhitelistActive
)
ERC20("", "")
Ownable()
Pausable()
{}
// ============================================================================================
// ERC20 Metadata
// ============================================================================================
function name() public view override(ERC20, IERC20Metadata) returns (string memory) {
return nameOfContract;
}
function symbol() public view override(ERC20, IERC20Metadata) returns (string memory) {
// prettier-ignore
// solhint-disable-next-line max-line-length
return string(abi.encodePacked("FraxlendV1 - ", collateralContract.safeSymbol(), "/", assetContract.safeSymbol()));
}
function decimals() public pure override(ERC20, IERC20Metadata) returns (uint8) {
return 18;
}
// totalSupply for fToken ERC20 compatibility
function totalSupply() public view override(ERC20, IERC20) returns (uint256) {
return totalAsset.shares;
}
// ============================================================================================
// Functions: Helpers
// ============================================================================================
function asset() external view returns (address) {
return address(assetContract);
}
function getConstants()
external
pure
returns (
uint256 _LTV_PRECISION,
uint256 _LIQ_PRECISION,
uint256 _UTIL_PREC,
uint256 _FEE_PRECISION,
uint256 _EXCHANGE_PRECISION,
uint64 _DEFAULT_INT,
uint16 _DEFAULT_PROTOCOL_FEE,
uint256 _MAX_PROTOCOL_FEE
)
{
_LTV_PRECISION = LTV_PRECISION;
_LIQ_PRECISION = LIQ_PRECISION;
_UTIL_PREC = UTIL_PREC;
_FEE_PRECISION = FEE_PRECISION;
_EXCHANGE_PRECISION = EXCHANGE_PRECISION;
_DEFAULT_INT = DEFAULT_INT;
_DEFAULT_PROTOCOL_FEE = DEFAULT_PROTOCOL_FEE;
_MAX_PROTOCOL_FEE = MAX_PROTOCOL_FEE;
}
/// @notice The ```getImmutableAddressBool``` function gets all the address and bool configs
/// @return _assetContract Address of asset
/// @return _collateralContract Address of collateral
/// @return _oracleMultiply Address of oracle numerator
/// @return _oracleDivide Address of oracle denominator
/// @return _rateContract Address of rate contract
/// @return _DEPLOYER_CONTRACT Address of deployer contract
/// @return _COMPTROLLER_ADDRESS Address of comptroller
/// @return _FRAXLEND_WHITELIST Address of whitelist
/// @return _borrowerWhitelistActive Boolean is borrower whitelist active
/// @return _lenderWhitelistActive Boolean is lender whitelist active
function getImmutableAddressBool()
external
view
returns (
address _assetContract,
address _collateralContract,
address _oracleMultiply,
address _oracleDivide,
address _rateContract,
address _DEPLOYER_CONTRACT,
address _COMPTROLLER_ADDRESS,
address _FRAXLEND_WHITELIST,
bool _borrowerWhitelistActive,
bool _lenderWhitelistActive
)
{
_assetContract = address(assetContract);
_collateralContract = address(collateralContract);
_oracleMultiply = oracleMultiply;
_oracleDivide = oracleDivide;
_rateContract = address(rateContract);
_DEPLOYER_CONTRACT = DEPLOYER_ADDRESS;
_COMPTROLLER_ADDRESS = COMPTROLLER_ADDRESS;
_FRAXLEND_WHITELIST = FRAXLEND_WHITELIST_ADDRESS;
_borrowerWhitelistActive = borrowerWhitelistActive;
_lenderWhitelistActive = lenderWhitelistActive;
}
/// @notice The ```getImmutableUint256``` function gets all uint256 config values
/// @return _oracleNormalization Oracle normalization factor
/// @return _maxLTV Maximum LTV
/// @return _cleanLiquidationFee Clean Liquidation Fee
/// @return _maturityDate Maturity Date
/// @return _penaltyRate Penalty Rate
function getImmutableUint256()
external
view
returns (
uint256 _oracleNormalization,
uint256 _maxLTV,
uint256 _cleanLiquidationFee,
uint256 _maturityDate,
uint256 _penaltyRate
)
{
_oracleNormalization = oracleNormalization;
_maxLTV = maxLTV;
_cleanLiquidationFee = cleanLiquidationFee;
_maturityDate = maturityDate;
_penaltyRate = penaltyRate;
}
/// @notice The ```getUserSnapshot``` function gets user level accounting data
/// @param _address The user address
/// @return _userAssetShares The user fToken balance
/// @return _userBorrowShares The user borrow shares
/// @return _userCollateralBalance The user collateral balance
function getUserSnapshot(address _address)
external
view
returns (
uint256 _userAssetShares,
uint256 _userBorrowShares,
uint256 _userCollateralBalance
)
{
_userAssetShares = balanceOf(_address);
_userBorrowShares = userBorrowShares[_address];
_userCollateralBalance = userCollateralBalance[_address];
}
/// @notice The ```getPairAccounting``` function gets all pair level accounting numbers
/// @return _totalAssetAmount Total assets deposited and interest accrued, total claims
/// @return _totalAssetShares Total fTokens
/// @return _totalBorrowAmount Total borrows
/// @return _totalBorrowShares Total borrow shares
/// @return _totalCollateral Total collateral
function getPairAccounting()
external
view
returns (
uint128 _totalAssetAmount,
uint128 _totalAssetShares,
uint128 _totalBorrowAmount,
uint128 _totalBorrowShares,
uint256 _totalCollateral
)
{
VaultAccount memory _totalAsset = totalAsset;
_totalAssetAmount = _totalAsset.amount;
_totalAssetShares = _totalAsset.shares;
VaultAccount memory _totalBorrow = totalBorrow;
_totalBorrowAmount = _totalBorrow.amount;
_totalBorrowShares = _totalBorrow.shares;
_totalCollateral = totalCollateral;
}
/// @notice The ```toBorrowShares``` function converts a given amount of borrow debt into the number of shares
/// @param _amount Amount of borrow
/// @param _roundUp Whether to roundup during division
function toBorrowShares(uint256 _amount, bool _roundUp) external view returns (uint256) {
return totalBorrow.toShares(_amount, _roundUp);
}
/// @notice The ```toBorrowAmount``` function converts a given amount of borrow debt into the number of shares
/// @param _shares Shares of borrow
/// @param _roundUp Whether to roundup during division
/// @return The amount of asset
function toBorrowAmount(uint256 _shares, bool _roundUp) external view returns (uint256) {
return totalBorrow.toAmount(_shares, _roundUp);
}
/// @notice The ```toAssetAmount``` function converts a given number of shares to an asset amount
/// @param _shares Shares of asset (fToken)
/// @param _roundUp Whether to round up after division
/// @return The amount of asset
function toAssetAmount(uint256 _shares, bool _roundUp) external view returns (uint256) {
return totalAsset.toAmount(_shares, _roundUp);
}
/// @notice The ```toAssetShares``` function converts a given asset amount to a number of asset shares (fTokens)
/// @param _amount The amount of asset
/// @param _roundUp Whether to round up after division
/// @return The number of shares (fTokens)
function toAssetShares(uint256 _amount, bool _roundUp) external view returns (uint256) {
return totalAsset.toShares(_amount, _roundUp);
}
// ============================================================================================
// Functions: Configuration
// ============================================================================================
/// @notice The ```SetTimeLock``` event fires when the TIME_LOCK_ADDRESS is set
/// @param _oldAddress The original address
/// @param _newAddress The new address
event SetTimeLock(address _oldAddress, address _newAddress);
/// @notice The ```setTimeLock``` function sets the TIME_LOCK address
/// @param _newAddress the new time lock address
function setTimeLock(address _newAddress) external {
if (msg.sender != TIME_LOCK_ADDRESS) revert OnlyTimeLock();
emit SetTimeLock(TIME_LOCK_ADDRESS, _newAddress);
TIME_LOCK_ADDRESS = _newAddress;
}
/// @notice The ```ChangeFee``` event first when the fee is changed
/// @param _newFee The new fee
event ChangeFee(uint32 _newFee);
/// @notice The ```changeFee``` function changes the protocol fee, max 50%
/// @param _newFee The new fee
function changeFee(uint32 _newFee) external whenNotPaused {
if (msg.sender != TIME_LOCK_ADDRESS) revert OnlyTimeLock();
if (_newFee > MAX_PROTOCOL_FEE) {
revert BadProtocolFee();
}
_addInterest();
currentRateInfo.feeToProtocolRate = _newFee;
emit ChangeFee(_newFee);
}
/// @notice The ```WithdrawFees``` event fires when the fees are withdrawn
/// @param _shares Number of _shares (fTokens) redeemed
/// @param _recipient To whom the assets were sent
/// @param _amountToTransfer The amount of fees redeemed
event WithdrawFees(uint128 _shares, address _recipient, uint256 _amountToTransfer);
/// @notice The ```withdrawFees``` function withdraws fees accumulated
/// @param _shares Number of fTokens to redeem
/// @param _recipient Address to send the assets
/// @return _amountToTransfer Amount of assets sent to recipient
function withdrawFees(uint128 _shares, address _recipient) external onlyOwner returns (uint256 _amountToTransfer) {
// Grab some data from state to save gas
VaultAccount memory _totalAsset = totalAsset;
VaultAccount memory _totalBorrow = totalBorrow;
// Take all available if 0 value passed
if (_shares == 0) _shares = uint128(balanceOf(address(this)));
// We must calculate this before we subtract from _totalAsset or invoke _burn
_amountToTransfer = _totalAsset.toAmount(_shares, true);
// Check for sufficient withdraw liquidity
uint256 _assetsAvailable = _totalAssetAvailable(_totalAsset, _totalBorrow);
if (_assetsAvailable < _amountToTransfer) {
revert InsufficientAssetsInContract(_assetsAvailable, _amountToTransfer);
}
// Effects: bookkeeping
_totalAsset.amount -= uint128(_amountToTransfer);
_totalAsset.shares -= _shares;
// Effects: write to states
// NOTE: will revert if _shares > balanceOf(address(this))
_burn(address(this), _shares);
totalAsset = _totalAsset;
// Interactions
assetContract.safeTransfer(_recipient, _amountToTransfer);
emit WithdrawFees(_shares, _recipient, _amountToTransfer);
}
/// @notice The ```SetSwapper``` event fires whenever a swapper is black or whitelisted
/// @param _swapper The swapper address
/// @param _approval The approval
event SetSwapper(address _swapper, bool _approval);
/// @notice The ```setSwapper``` function is called to black or whitelist a given swapper address
/// @dev
/// @param _swapper The swapper address
/// @param _approval The approval
function setSwapper(address _swapper, bool _approval) external onlyOwner {
swappers[_swapper] = _approval;
emit SetSwapper(_swapper, _approval);
}
/// @notice The ```SetApprovedLender``` event fires when a lender is black or whitelisted
/// @param _address The address
/// @param _approval The approval
event SetApprovedLender(address indexed _address, bool _approval);
/// @notice The ```setApprovedLenders``` function sets a given set of addresses to the whitelist
/// @dev Cannot black list self
/// @param _lenders The addresses who's status will be set
/// @param _approval The approval status
function setApprovedLenders(address[] calldata _lenders, bool _approval) external approvedLender(msg.sender) {
for (uint256 i = 0; i < _lenders.length; i++) {
// Do not set when _approval == false and _lender == msg.sender
if (_approval || _lenders[i] != msg.sender) {
approvedLenders[_lenders[i]] = _approval;
emit SetApprovedLender(_lenders[i], _approval);
}
}
}
/// @notice The ```SetApprovedBorrower``` event fires when a borrower is black or whitelisted
/// @param _address The address
/// @param _approval The approval
event SetApprovedBorrower(address indexed _address, bool _approval);
/// @notice The ```setApprovedBorrowers``` function sets a given array of addresses to the whitelist
/// @dev Cannot black list self
/// @param _borrowers The addresses who's status will be set
/// @param _approval The approval status
function setApprovedBorrowers(address[] calldata _borrowers, bool _approval) external approvedBorrower {
for (uint256 i = 0; i < _borrowers.length; i++) {
// Do not set when _approval == false and _borrower == msg.sender
if (_approval || _borrowers[i] != msg.sender) {
approvedBorrowers[_borrowers[i]] = _approval;
emit SetApprovedBorrower(_borrowers[i], _approval);
}
}
}
function pause() external {
if (
msg.sender != CIRCUIT_BREAKER_ADDRESS &&
msg.sender != COMPTROLLER_ADDRESS &&
msg.sender != owner() &&
msg.sender != DEPLOYER_ADDRESS
) {
revert ProtocolOrOwnerOnly();
}
_addInterest(); // accrue any interest prior to pausing as it won't accrue during pause
_pause();
}
function unpause() external {
if (msg.sender != COMPTROLLER_ADDRESS && msg.sender != owner()) {
revert ProtocolOrOwnerOnly();
}
// Resets the lastTimestamp which has the effect of no interest accruing over the pause period
_addInterest();
_unpause();
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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);
/**
* @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 `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, 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 `from` to `to` 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 from,
address to,
uint256 amount
) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
pragma solidity ^0.8.0;
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
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() {
_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 making 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;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface AggregatorV3Interface {
function decimals() external view returns (uint8);
function description() external view returns (string memory);
function version() external view returns (uint256);
// getRoundData and latestRoundData should both raise "No data present"
// if they do not have data to report, instead of returning unset values
// which could be misinterpreted as actual reported values.
function getRoundData(uint80 _roundId)
external
view
returns (
uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt,
uint80 answeredInRound
);
function latestRoundData()
external
view
returns (
uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt,
uint80 answeredInRound
);
}
// SPDX-License-Identifier: ISC
pragma solidity ^0.8.16;
// ====================================================================
// | ______ _______ |
// | / _____________ __ __ / ____(_____ ____ _____ ________ |
// | / /_ / ___/ __ `| |/_/ / /_ / / __ \/ __ `/ __ \/ ___/ _ \ |
// | / __/ / / / /_/ _> < / __/ / / / / / /_/ / / / / /__/ __/ |
// | /_/ /_/ \__,_/_/|_| /_/ /_/_/ /_/\__,_/_/ /_/\___/\___/ |
// | |
// ====================================================================
// ===================== FraxlendPairConstants ========================
// ====================================================================
// Frax Finance: https://github.com/FraxFinance
// Primary Author
// Drake Evans: https://github.com/DrakeEvans
// Reviewers
// Dennis: https://github.com/denett
// Sam Kazemian: https://github.com/samkazemian
// Travis Moore: https://github.com/FortisFortuna
// Jack Corddry: https://github.com/corddry
// Rich Gee: https://github.com/zer0blockchain
// ====================================================================
abstract contract FraxlendPairConstants {
// ============================================================================================
// Constants
// ============================================================================================
// Precision settings
uint256 internal constant LTV_PRECISION = 1e5; // 5 decimals
uint256 internal constant LIQ_PRECISION = 1e5;
uint256 internal constant UTIL_PREC = 1e5;
uint256 internal constant FEE_PRECISION = 1e5;
uint256 internal constant EXCHANGE_PRECISION = 1e18;
// Default Interest Rate (if borrows = 0)
uint64 internal constant DEFAULT_INT = 158049988; // 0.5% annual rate 1e18 precision
// Protocol Fee
uint16 internal constant DEFAULT_PROTOCOL_FEE = 0; // 1e5 precision
uint256 internal constant MAX_PROTOCOL_FEE = 5e4; // 50% 1e5 precision
error Insolvent(uint256 _borrow, uint256 _collateral, uint256 _exchangeRate);
error BorrowerSolvent();
error OnlyApprovedBorrowers();
error OnlyApprovedLenders();
error PastMaturity();
error ProtocolOrOwnerOnly();
error OracleLTEZero(address _oracle);
error InsufficientAssetsInContract(uint256 _assets, uint256 _request);
error NotOnWhitelist(address _address);
error NotDeployer();
error NameEmpty();
error AlreadyInitialized();
error SlippageTooHigh(uint256 _minOut, uint256 _actual);
error BadSwapper();
error InvalidPath(address _expected, address _actual);
error BadProtocolFee();
error BorrowerWhitelistRequired();
error OnlyTimeLock();
error PriceTooLarge();
error PastDeadline(uint256 _blockTimestamp, uint256 _deadline);
}
// SPDX-License-Identifier: ISC
pragma solidity ^0.8.16;
// ====================================================================
// | ______ _______ |
// | / _____________ __ __ / ____(_____ ____ _____ ________ |
// | / /_ / ___/ __ `| |/_/ / /_ / / __ \/ __ `/ __ \/ ___/ _ \ |
// | / __/ / / / /_/ _> < / __/ / / / / / /_/ / / / / /__/ __/ |
// | /_/ /_/ \__,_/_/|_| /_/ /_/_/ /_/\__,_/_/ /_/\___/\___/ |
// | |
// ====================================================================
// ========================= FraxlendPairCore =========================
// ====================================================================
// Frax Finance: https://github.com/FraxFinance
// Primary Author
// Drake Evans: https://github.com/DrakeEvans
// Reviewers
// Dennis: https://github.com/denett
// Sam Kazemian: https://github.com/samkazemian
// Travis Moore: https://github.com/FortisFortuna
// Jack Corddry: https://github.com/corddry
// Rich Gee: https://github.com/zer0blockchain
// ====================================================================
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/math/SafeCast.sol";
import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
import "./FraxlendPairConstants.sol";
import "./libraries/VaultAccount.sol";
import "./libraries/SafeERC20.sol";
import "./interfaces/IERC4626.sol";
import "./interfaces/IFraxlendWhitelist.sol";
import "./interfaces/IRateCalculator.sol";
import "./interfaces/ISwapper.sol";
/// @title FraxlendPairCore
/// @author Drake Evans (Frax Finance) https://github.com/drakeevans
/// @notice An abstract contract which contains the core logic and storage for the FraxlendPair
abstract contract FraxlendPairCore is FraxlendPairConstants, ERC20, Ownable, Pausable, ReentrancyGuard {
using VaultAccountingLibrary for VaultAccount;
using SafeERC20 for IERC20;
using SafeCast for uint256;
string public version = "1.0.0";
// ============================================================================================
// Settings set by constructor() & initialize()
// ============================================================================================
// Asset and collateral contracts
IERC20 internal immutable assetContract;
IERC20 public immutable collateralContract;
// Oracle wrapper contract and oracleData
address public immutable oracleMultiply;
address public immutable oracleDivide;
uint256 public immutable oracleNormalization;
// LTV Settings
uint256 public immutable maxLTV;
// Liquidation Fee
uint256 public immutable cleanLiquidationFee;
uint256 public immutable dirtyLiquidationFee;
// Interest Rate Calculator Contract
IRateCalculator public immutable rateContract; // For complex rate calculations
bytes public rateInitCallData; // Optional extra data from init function to be passed to rate calculator
// Swapper
mapping(address => bool) public swappers; // approved swapper addresses
// Deployer
address public immutable DEPLOYER_ADDRESS;
// Admin contracts
address public immutable CIRCUIT_BREAKER_ADDRESS;
address public immutable COMPTROLLER_ADDRESS;
address public TIME_LOCK_ADDRESS;
// Dependencies
address public immutable FRAXLEND_WHITELIST_ADDRESS;
// ERC20 token name, accessible via name()
string internal nameOfContract;
// Maturity Date & Penalty Interest Rate (per Sec)
uint256 public immutable maturityDate;
uint256 public immutable penaltyRate;
// ============================================================================================
// Storage
// ============================================================================================
/// @notice Stores information about the current interest rate
/// @dev struct is packed to reduce SLOADs. feeToProtocolRate is 1e5 precision, ratePerSec is 1e18 precision
CurrentRateInfo public currentRateInfo;
struct CurrentRateInfo {
uint64 lastBlock;
uint64 feeToProtocolRate; // Fee amount 1e5 precision
uint64 lastTimestamp;
uint64 ratePerSec;
}
/// @notice Stores information about the current exchange rate. Collateral:Asset ratio
/// @dev Struct packed to save SLOADs. Amount of Collateral Token to buy 1e18 Asset Token
ExchangeRateInfo public exchangeRateInfo;
struct ExchangeRateInfo {
uint32 lastTimestamp;
uint224 exchangeRate; // collateral:asset ratio. i.e. how much collateral to buy 1e18 asset
}
// Contract Level Accounting
VaultAccount public totalAsset; // amount = total amount of assets, shares = total shares outstanding
VaultAccount public totalBorrow; // amount = total borrow amount with interest accrued, shares = total shares outstanding
uint256 public totalCollateral; // total amount of collateral in contract
// User Level Accounting
/// @notice Stores the balance of collateral for each user
mapping(address => uint256) public userCollateralBalance; // amount of collateral each user is backed
/// @notice Stores the balance of borrow shares for each user
mapping(address => uint256) public userBorrowShares; // represents the shares held by individuals
// NOTE: user shares of assets are represented as ERC-20 tokens and accessible via balanceOf()
// Internal Whitelists
bool public immutable borrowerWhitelistActive;
mapping(address => bool) public approvedBorrowers;
bool public immutable lenderWhitelistActive;
mapping(address => bool) public approvedLenders;
// ============================================================================================
// Initialize
// ============================================================================================
/// @notice The ```constructor``` function is called on deployment
/// @param _configData abi.encode(address _asset, address _collateral, address _oracleMultiply, address _oracleDivide, uint256 _oracleNormalization, address _rateContract, bytes memory _rateInitData)
/// @param _maxLTV The Maximum Loan-To-Value for a borrower to be considered solvent (1e5 precision)
/// @param _liquidationFee The fee paid to liquidators given as a % of the repayment (1e5 precision)
/// @param _maturityDate The maturityDate date of the Pair
/// @param _penaltyRate The interest rate after maturity date
/// @param _isBorrowerWhitelistActive Enables borrower whitelist
/// @param _isLenderWhitelistActive Enables lender whitelist
constructor(
bytes memory _configData,
bytes memory _immutables,
uint256 _maxLTV,
uint256 _liquidationFee,
uint256 _maturityDate,
uint256 _penaltyRate,
bool _isBorrowerWhitelistActive,
bool _isLenderWhitelistActive
) {
// Handle Immutables Configuration
{
(
address _circuitBreaker,
address _comptrollerAddress,
address _timeLockAddress,
address _fraxlendWhitelistAddress
) = abi.decode(_immutables, (address, address, address, address));
// Deployer contract
DEPLOYER_ADDRESS = msg.sender;
CIRCUIT_BREAKER_ADDRESS = _circuitBreaker;
COMPTROLLER_ADDRESS = _comptrollerAddress;
TIME_LOCK_ADDRESS = _timeLockAddress;
FRAXLEND_WHITELIST_ADDRESS = _fraxlendWhitelistAddress;
}
{
(
address _asset,
address _collateral,
address _oracleMultiply,
address _oracleDivide,
uint256 _oracleNormalization,
address _rateContract,
) = abi.decode(_configData, (address, address, address, address, uint256, address, bytes));
// Pair Settings
assetContract = IERC20(_asset);
collateralContract = IERC20(_collateral);
currentRateInfo.feeToProtocolRate = DEFAULT_PROTOCOL_FEE;
cleanLiquidationFee = _liquidationFee;
dirtyLiquidationFee = (_liquidationFee * 90000) / LIQ_PRECISION; // 90% of clean fee
if (_maxLTV >= LTV_PRECISION && !_isBorrowerWhitelistActive) revert BorrowerWhitelistRequired();
maxLTV = _maxLTV;
// Oracle Settings
{
IFraxlendWhitelist _fraxlendWhitelist = IFraxlendWhitelist(FRAXLEND_WHITELIST_ADDRESS);
// Check that oracles are on the whitelist
if (_oracleMultiply != address(0) && !_fraxlendWhitelist.oracleContractWhitelist(_oracleMultiply)) {
revert NotOnWhitelist(_oracleMultiply);
}
if (_oracleDivide != address(0) && !_fraxlendWhitelist.oracleContractWhitelist(_oracleDivide)) {
revert NotOnWhitelist(_oracleDivide);
}
// Write oracleData to storage
oracleMultiply = _oracleMultiply;
oracleDivide = _oracleDivide;
oracleNormalization = _oracleNormalization;
// Rate Settings
if (!_fraxlendWhitelist.rateContractWhitelist(_rateContract)) {
revert NotOnWhitelist(_rateContract);
}
}
rateContract = IRateCalculator(_rateContract);
}
// Set approved borrowers whitelist
borrowerWhitelistActive = _isBorrowerWhitelistActive;
// Set approved lenders whitelist active
lenderWhitelistActive = _isLenderWhitelistActive;
// Set maturity date & penalty interest rate
maturityDate = _maturityDate;
penaltyRate = _penaltyRate;
}
/// @notice The ```initialize``` function is called immediately after deployment
/// @dev This function can only be called by the deployer
/// @param _name The name of the contract
/// @param _approvedBorrowers An array of approved borrower addresses
/// @param _approvedLenders An array of approved lender addresses
/// @param _rateInitCallData The configuration data for the Rate Calculator contract
function initialize(
string calldata _name,
address[] calldata _approvedBorrowers,
address[] calldata _approvedLenders,
bytes calldata _rateInitCallData
) external {
if (msg.sender != DEPLOYER_ADDRESS) {
revert NotDeployer();
}
if (bytes(_name).length == 0) {
revert NameEmpty();
}
if (bytes(nameOfContract).length != 0) {
revert AlreadyInitialized();
}
// Set name
nameOfContract = _name;
// Set approved borrowers
for (uint256 i = 0; i < _approvedBorrowers.length; ++i) {
approvedBorrowers[_approvedBorrowers[i]] = true;
}
// Set approved lenders
for (uint256 i = 0; i < _approvedLenders.length; ++i) {
approvedLenders[_approvedLenders[i]] = true;
}
// Reverts if init data is not valid
IRateCalculator(rateContract).requireValidInitData(_rateInitCallData);
// Set rate init Data
rateInitCallData = _rateInitCallData;
// Instantiate Interest
_addInterest();
// Instantiate Exchange Rate
_updateExchangeRate();
}
// ============================================================================================
// Internal Helpers
// ============================================================================================
/// @notice The ```_totalAssetAvailable``` function returns the total balance of Asset Tokens in the contract
/// @param _totalAsset VaultAccount struct which stores total amount and shares for assets
/// @param _totalBorrow VaultAccount struct which stores total amount and shares for borrows
/// @return The balance of Asset Tokens held by contract
function _totalAssetAvailable(VaultAccount memory _totalAsset, VaultAccount memory _totalBorrow)
internal
pure
returns (uint256)
{
return _totalAsset.amount - _totalBorrow.amount;
}
/// @notice The ```_isSolvent``` function determines if a given borrower is solvent given an exchange rate
/// @param _borrower The borrower address to check
/// @param _exchangeRate The exchange rate, i.e. the amount of collateral to buy 1e18 asset
/// @return Whether borrower is solvent
function _isSolvent(address _borrower, uint256 _exchangeRate) internal view returns (bool) {
if (maxLTV == 0) return true;
uint256 _borrowerAmount = totalBorrow.toAmount(userBorrowShares[_borrower], true);
if (_borrowerAmount == 0) return true;
uint256 _collateralAmount = userCollateralBalance[_borrower];
if (_collateralAmount == 0) return false;
uint256 _ltv = (((_borrowerAmount * _exchangeRate) / EXCHANGE_PRECISION) * LTV_PRECISION) / _collateralAmount;
return _ltv <= maxLTV;
}
/// @notice The ```_isPastMaturity``` function determines if the current block timestamp is past the maturityDate date
/// @return Whether or not the debt is past maturity
function _isPastMaturity() internal view returns (bool) {
return maturityDate != 0 && block.timestamp > maturityDate;
}
// ============================================================================================
// Modifiers
// ============================================================================================
/// @notice Checks for solvency AFTER executing contract code
/// @param _borrower The borrower whose solvency we will check
modifier isSolvent(address _borrower) {
_;
if (!_isSolvent(_borrower, exchangeRateInfo.exchangeRate)) {
revert Insolvent(
totalBorrow.toAmount(userBorrowShares[_borrower], true),
userCollateralBalance[_borrower],
exchangeRateInfo.exchangeRate
);
}
}
/// @notice Checks if msg.sender is an approved Borrower
modifier approvedBorrower() {
if (borrowerWhitelistActive && !approvedBorrowers[msg.sender]) {
revert OnlyApprovedBorrowers();
}
_;
}
/// @notice Checks if msg.sender and _receiver are both an approved Lender
/// @param _receiver An additional receiver address to check
modifier approvedLender(address _receiver) {
if (lenderWhitelistActive && (!approvedLenders[msg.sender] || !approvedLenders[_receiver])) {
revert OnlyApprovedLenders();
}
_;
}
/// @notice Ensure function is not called when passed maturity
modifier isNotPastMaturity() {
if (_isPastMaturity()) {
revert PastMaturity();
}
_;
}
// ============================================================================================
// Functions: Interest Accumulation and Adjustment
// ============================================================================================
/// @notice The ```AddInterest``` event is emitted when interest is accrued by borrowers
/// @param _interestEarned The total interest accrued by all borrowers
/// @param _rate The interest rate used to calculate accrued interest
/// @param _deltaTime The time elapsed since last interest accrual
/// @param _feesAmount The amount of fees paid to protocol
/// @param _feesShare The amount of shares distributed to protocol
event AddInterest(
uint256 _interestEarned,
uint256 _rate,
uint256 _deltaTime,
uint256 _feesAmount,
uint256 _feesShare
);
/// @notice The ```UpdateRate``` event is emitted when the interest rate is updated
/// @param _ratePerSec The old interest rate (per second)
/// @param _deltaTime The time elapsed since last update
/// @param _utilizationRate The utilization of assets in the Pair
/// @param _newRatePerSec The new interest rate (per second)
event UpdateRate(uint256 _ratePerSec, uint256 _deltaTime, uint256 _utilizationRate, uint256 _newRatePerSec);
/// @notice The ```addInterest``` function is a public implementation of _addInterest and allows 3rd parties to trigger interest accrual
/// @return _interestEarned The amount of interest accrued by all borrowers
function addInterest()
external
nonReentrant
returns (
uint256 _interestEarned,
uint256 _feesAmount,
uint256 _feesShare,
uint64 _newRate
)
{
return _addInterest();
}
/// @notice The ```_addInterest``` function is invoked prior to every external function and is used to accrue interest and update interest rate
/// @dev Can only called once per block
/// @return _interestEarned The amount of interest accrued by all borrowers
function _addInterest()
internal
returns (
uint256 _interestEarned,
uint256 _feesAmount,
uint256 _feesShare,
uint64 _newRate
)
{
// Add interest only once per block
CurrentRateInfo memory _currentRateInfo = currentRateInfo;
if (_currentRateInfo.lastTimestamp == block.timestamp) {
_newRate = _currentRateInfo.ratePerSec;
return (_interestEarned, _feesAmount, _feesShare, _newRate);
}
// Pull some data from storage to save gas
VaultAccount memory _totalAsset = totalAsset;
VaultAccount memory _totalBorrow = totalBorrow;
// If there are no borrows or contract is paused, no interest accrues and we reset interest rate
if (_totalBorrow.shares == 0 || paused()) {
if (!paused()) {
_currentRateInfo.ratePerSec = DEFAULT_INT;
}
_currentRateInfo.lastTimestamp = uint64(block.timestamp);
_currentRateInfo.lastBlock = uint64(block.number);
// Effects: write to storage
currentRateInfo = _currentRateInfo;
} else {
// We know totalBorrow.shares > 0
uint256 _deltaTime = block.timestamp - _currentRateInfo.lastTimestamp;
// NOTE: Violates Checks-Effects-Interactions pattern
// Be sure to mark external version NONREENTRANT (even though rateContract is trusted)
// Calc new rate
uint256 _utilizationRate = (UTIL_PREC * _totalBorrow.amount) / _totalAsset.amount;
if (_isPastMaturity()) {
_newRate = uint64(penaltyRate);
} else {
bytes memory _rateData = abi.encode(
_currentRateInfo.ratePerSec,
_deltaTime,
_utilizationRate,
block.number - _currentRateInfo.lastBlock
);
_newRate = IRateCalculator(rateContract).getNewRate(_rateData, rateInitCallData);
}
// Event must be here to use non-mutated values
emit UpdateRate(_currentRateInfo.ratePerSec, _deltaTime, _utilizationRate, _newRate);
// Effects: bookkeeping
_currentRateInfo.ratePerSec = _newRate;
_currentRateInfo.lastTimestamp = uint64(block.timestamp);
_currentRateInfo.lastBlock = uint64(block.number);
// Calculate interest accrued
_interestEarned = (_deltaTime * _totalBorrow.amount * _currentRateInfo.ratePerSec) / 1e18;
// Accumulate interest and fees, only if no overflow upon casting
if (
_interestEarned + _totalBorrow.amount <= type(uint128).max &&
_interestEarned + _totalAsset.amount <= type(uint128).max
) {
_totalBorrow.amount += uint128(_interestEarned);
_totalAsset.amount += uint128(_interestEarned);
if (_currentRateInfo.feeToProtocolRate > 0) {
_feesAmount = (_interestEarned * _currentRateInfo.feeToProtocolRate) / FEE_PRECISION;
_feesShare = (_feesAmount * _totalAsset.shares) / (_totalAsset.amount - _feesAmount);
// Effects: Give new shares to this contract, effectively diluting lenders an amount equal to the fees
// We can safely cast because _feesShare < _feesAmount < interestEarned which is always less than uint128
_totalAsset.shares += uint128(_feesShare);
// Effects: write to storage
_mint(address(this), _feesShare);
}
emit AddInterest(_interestEarned, _currentRateInfo.ratePerSec, _deltaTime, _feesAmount, _feesShare);
}
// Effects: write to storage
totalAsset = _totalAsset;
currentRateInfo = _currentRateInfo;
totalBorrow = _totalBorrow;
}
}
// ============================================================================================
// Functions: ExchangeRate
// ============================================================================================
/// @notice The ```UpdateExchangeRate``` event is emitted when the Collateral:Asset exchange rate is updated
/// @param _rate The new rate given as the amount of Collateral Token to buy 1e18 Asset Token
event UpdateExchangeRate(uint256 _rate);
/// @notice The ```updateExchangeRate``` function is the external implementation of _updateExchangeRate.
/// @dev This function is invoked at most once per block as these queries can be expensive
/// @return _exchangeRate The new exchange rate
function updateExchangeRate() external nonReentrant returns (uint256 _exchangeRate) {
_exchangeRate = _updateExchangeRate();
}
/// @notice The ```_updateExchangeRate``` function retrieves the latest exchange rate. i.e how much collateral to buy 1e18 asset.
/// @dev This function is invoked at most once per block as these queries can be expensive
/// @return _exchangeRate The new exchange rate
function _updateExchangeRate() internal returns (uint256 _exchangeRate) {
ExchangeRateInfo memory _exchangeRateInfo = exchangeRateInfo;
if (_exchangeRateInfo.lastTimestamp == block.timestamp) {
return _exchangeRate = _exchangeRateInfo.exchangeRate;
}
uint256 _price = uint256(1e36);
if (oracleMultiply != address(0)) {
(, int256 _answer, , , ) = AggregatorV3Interface(oracleMultiply).latestRoundData();
if (_answer <= 0) {
revert OracleLTEZero(oracleMultiply);
}
_price = _price * uint256(_answer);
}
if (oracleDivide != address(0)) {
(, int256 _answer, , , ) = AggregatorV3Interface(oracleDivide).latestRoundData();
if (_answer <= 0) {
revert OracleLTEZero(oracleDivide);
}
_price = _price / uint256(_answer);
}
_exchangeRate = _price / oracleNormalization;
// write to storage, if no overflow
if (_exchangeRate > type(uint224).max) revert PriceTooLarge();
_exchangeRateInfo.exchangeRate = uint224(_exchangeRate);
_exchangeRateInfo.lastTimestamp = uint32(block.timestamp);
exchangeRateInfo = _exchangeRateInfo;
emit UpdateExchangeRate(_exchangeRate);
}
// ============================================================================================
// Functions: Lending
// ============================================================================================
/// @notice The ```Deposit``` event fires when a user deposits assets to the pair
/// @param caller the msg.sender
/// @param owner the account the fTokens are sent to
/// @param assets the amount of assets deposited
/// @param shares the number of fTokens minted
event Deposit(address indexed caller, address indexed owner, uint256 assets, uint256 shares);
/// @notice The ```_deposit``` function is the internal implementation for lending assets
/// @dev Caller must invoke ```ERC20.approve``` on the Asset Token contract prior to calling function
/// @param _totalAsset An in memory VaultAccount struct representing the total amounts and shares for the Asset Token
/// @param _amount The amount of Asset Token to be transferred
/// @param _shares The amount of Asset Shares (fTokens) to be minted
/// @param _receiver The address to receive the Asset Shares (fTokens)
function _deposit(
VaultAccount memory _totalAsset,
uint128 _amount,
uint128 _shares,
address _receiver
) internal {
// Effects: bookkeeping
_totalAsset.amount += _amount;
_totalAsset.shares += _shares;
// Effects: write back to storage
_mint(_receiver, _shares);
totalAsset = _totalAsset;
// Interactions
assetContract.safeTransferFrom(msg.sender, address(this), _amount);
emit Deposit(msg.sender, _receiver, _amount, _shares);
}
/// @notice The ```deposit``` function allows a user to Lend Assets by specifying the amount of Asset Tokens to lend
/// @dev Caller must invoke ```ERC20.approve``` on the Asset Token contract prior to calling function
/// @param _amount The amount of Asset Token to transfer to Pair
/// @param _receiver The address to receive the Asset Shares (fTokens)
/// @return _sharesReceived The number of fTokens received for the deposit
function deposit(uint256 _amount, address _receiver)
external
nonReentrant
isNotPastMaturity
whenNotPaused
approvedLender(_receiver)
returns (uint256 _sharesReceived)
{
_addInterest();
VaultAccount memory _totalAsset = totalAsset;
_sharesReceived = _totalAsset.toShares(_amount, false);
_deposit(_totalAsset, _amount.toUint128(), _sharesReceived.toUint128(), _receiver);
}
/// @notice The ```Withdraw``` event fires when a user redeems their fTokens for the underlying asset
/// @param caller the msg.sender
/// @param receiver The address to which the underlying asset will be transferred to
/// @param owner The owner of the fTokens
/// @param assets The assets transferred
/// @param shares The number of fTokens burned
event Withdraw(
address indexed caller,
address indexed receiver,
address indexed owner,
uint256 assets,
uint256 shares
);
/// @notice The ```_redeem``` function is an internal implementation which allows a Lender to pull their Asset Tokens out of the Pair
/// @dev Caller must invoke ```ERC20.approve``` on the Asset Token contract prior to calling function
/// @param _totalAsset An in-memory VaultAccount struct which holds the total amount of Asset Tokens and the total number of Asset Shares (fTokens)
/// @param _amountToReturn The number of Asset Tokens to return
/// @param _shares The number of Asset Shares (fTokens) to burn
/// @param _receiver The address to which the Asset Tokens will be transferred
/// @param _owner The owner of the Asset Shares (fTokens)
function _redeem(
VaultAccount memory _totalAsset,
uint128 _amountToReturn,
uint128 _shares,
address _receiver,
address _owner
) internal {
if (msg.sender != _owner) {
uint256 allowed = allowance(_owner, msg.sender);
// NOTE: This will revert on underflow ensuring that allowance > shares
if (allowed != type(uint256).max) _approve(_owner, msg.sender, allowed - _shares);
}
// Check for sufficient withdraw liquidity
uint256 _assetsAvailable = _totalAssetAvailable(_totalAsset, totalBorrow);
if (_assetsAvailable < _amountToReturn) {
revert InsufficientAssetsInContract(_assetsAvailable, _amountToReturn);
}
// Effects: bookkeeping
_totalAsset.amount -= _amountToReturn;
_totalAsset.shares -= _shares;
// Effects: write to storage
totalAsset = _totalAsset;
_burn(_owner, _shares);
// Interactions
assetContract.safeTransfer(_receiver, _amountToReturn);
emit Withdraw(msg.sender, _receiver, _owner, _amountToReturn, _shares);
}
/// @notice The ```redeem``` function allows the caller to redeem their Asset Shares for Asset Tokens
/// @param _shares The number of Asset Shares (fTokens) to burn for Asset Tokens
/// @param _receiver The address to which the Asset Tokens will be transferred
/// @param _owner The owner of the Asset Shares (fTokens)
/// @return _amountToReturn The amount of Asset Tokens to be transferred
function redeem(
uint256 _shares,
address _receiver,
address _owner
) external nonReentrant returns (uint256 _amountToReturn) {
_addInterest();
VaultAccount memory _totalAsset = totalAsset;
_amountToReturn = _totalAsset.toAmount(_shares, false);
_redeem(_totalAsset, _amountToReturn.toUint128(), _shares.toUint128(), _receiver, _owner);
}
// ============================================================================================
// Functions: Borrowing
// ============================================================================================
/// @notice The ```BorrowAsset``` event is emitted when a borrower increases their position
/// @param _borrower The borrower whose account was debited
/// @param _receiver The address to which the Asset Tokens were transferred
/// @param _borrowAmount The amount of Asset Tokens transferred
/// @param _sharesAdded The number of Borrow Shares the borrower was debited
event BorrowAsset(
address indexed _borrower,
address indexed _receiver,
uint256 _borrowAmount,
uint256 _sharesAdded
);
/// @notice The ```_borrowAsset``` function is the internal implementation for borrowing assets
/// @param _borrowAmount The amount of the Asset Token to borrow
/// @param _receiver The address to receive the Asset Tokens
/// @return _sharesAdded The amount of borrow shares the msg.sender will be debited
function _borrowAsset(uint128 _borrowAmount, address _receiver) internal returns (uint256 _sharesAdded) {
VaultAccount memory _totalBorrow = totalBorrow;
// Check available capital
uint256 _assetsAvailable = _totalAssetAvailable(totalAsset, _totalBorrow);
if (_assetsAvailable < _borrowAmount) {
revert InsufficientAssetsInContract(_assetsAvailable, _borrowAmount);
}
// Effects: Bookkeeping to add shares & amounts to total Borrow accounting
_sharesAdded = _totalBorrow.toShares(_borrowAmount, true);
_totalBorrow.amount += _borrowAmount;
_totalBorrow.shares += uint128(_sharesAdded);
// NOTE: we can safely cast here because shares are always less than amount and _borrowAmount is uint128
// Effects: write back to storage
totalBorrow = _totalBorrow;
userBorrowShares[msg.sender] += _sharesAdded;
// Interactions
if (_receiver != address(this)) {
assetContract.safeTransfer(_receiver, _borrowAmount);
}
emit BorrowAsset(msg.sender, _receiver, _borrowAmount, _sharesAdded);
}
/// @notice The ```borrowAsset``` function allows a user to open/increase a borrow position
/// @dev Borrower must call ```ERC20.approve``` on the Collateral Token contract if applicable
/// @param _borrowAmount The amount of Asset Token to borrow
/// @param _collateralAmount The amount of Collateral Token to transfer to Pair
/// @param _receiver The address which will receive the Asset Tokens
/// @return _shares The number of borrow Shares the msg.sender will be debited
function borrowAsset(
uint256 _borrowAmount,
uint256 _collateralAmount,
address _receiver
)
external
isNotPastMaturity
whenNotPaused
nonReentrant
isSolvent(msg.sender)
approvedBorrower
returns (uint256 _shares)
{
_addInterest();
_updateExchangeRate();
if (_collateralAmount > 0) {
_addCollateral(msg.sender, _collateralAmount, msg.sender);
}
_shares = _borrowAsset(_borrowAmount.toUint128(), _receiver);
}
event AddCollateral(address indexed _sender, address indexed _borrower, uint256 _collateralAmount);
/// @notice The ```_addCollateral``` function is an internal implementation for adding collateral to a borrowers position
/// @param _sender The source of funds for the new collateral
/// @param _collateralAmount The amount of Collateral Token to be transferred
/// @param _borrower The borrower account for which the collateral should be credited
function _addCollateral(
address _sender,
uint256 _collateralAmount,
address _borrower
) internal {
// Effects: write to state
userCollateralBalance[_borrower] += _collateralAmount;
totalCollateral += _collateralAmount;
// Interactions
if (_sender != address(this)) {
collateralContract.safeTransferFrom(_sender, address(this), _collateralAmount);
}
emit AddCollateral(_sender, _borrower, _collateralAmount);
}
/// @notice The ```addCollateral``` function allows the caller to add Collateral Token to a borrowers position
/// @dev msg.sender must call ERC20.approve() on the Collateral Token contract prior to invocation
/// @param _collateralAmount The amount of Collateral Token to be added to borrower's position
/// @param _borrower The account to be credited
function addCollateral(uint256 _collateralAmount, address _borrower) external nonReentrant isNotPastMaturity {
_addInterest();
_addCollateral(msg.sender, _collateralAmount, _borrower);
}
/// @notice The ```RemoveCollateral``` event is emitted when collateral is removed from a borrower's position
/// @param _sender The account from which funds are transferred
/// @param _collateralAmount The amount of Collateral Token to be transferred
/// @param _receiver The address to which Collateral Tokens will be transferred
event RemoveCollateral(
address indexed _sender,
uint256 _collateralAmount,
address indexed _receiver,
address indexed _borrower
);
/// @notice The ```_removeCollateral``` function is the internal implementation for removing collateral from a borrower's position
/// @param _collateralAmount The amount of Collateral Token to remove from the borrower's position
/// @param _receiver The address to receive the Collateral Token transferred
/// @param _borrower The borrower whose account will be debited the Collateral amount
function _removeCollateral(
uint256 _collateralAmount,
address _receiver,
address _borrower
) internal {
// Effects: write to state
// Following line will revert on underflow if _collateralAmount > userCollateralBalance
userCollateralBalance[_borrower] -= _collateralAmount;
// Following line will revert on underflow if totalCollateral < _collateralAmount
totalCollateral -= _collateralAmount;
// Interactions
if (_receiver != address(this)) {
collateralContract.safeTransfer(_receiver, _collateralAmount);
}
emit RemoveCollateral(msg.sender, _collateralAmount, _receiver, _borrower);
}
/// @notice The ```removeCollateral``` function is used to remove collateral from msg.sender's borrow position
/// @dev msg.sender must be solvent after invocation or transaction will revert
/// @param _collateralAmount The amount of Collateral Token to transfer
/// @param _receiver The address to receive the transferred funds
function removeCollateral(uint256 _collateralAmount, address _receiver)
external
nonReentrant
isSolvent(msg.sender)
{
_addInterest();
// Note: exchange rate is irrelevant when borrower has no debt shares
if (userBorrowShares[msg.sender] > 0) {
_updateExchangeRate();
}
_removeCollateral(_collateralAmount, _receiver, msg.sender);
}
/// @notice The ```RepayAsset``` event is emitted whenever a debt position is repaid
/// @param _payer The address paying for the repayment
/// @param _borrower The borrower whose account will be credited
/// @param _amountToRepay The amount of Asset token to be transferred
/// @param _shares The amount of Borrow Shares which will be debited from the borrower after repayment
event RepayAsset(address indexed _payer, address indexed _borrower, uint256 _amountToRepay, uint256 _shares);
/// @notice The ```_repayAsset``` function is the internal implementation for repaying a borrow position
/// @dev The payer must have called ERC20.approve() on the Asset Token contract prior to invocation
/// @param _totalBorrow An in memory copy of the totalBorrow VaultAccount struct
/// @param _amountToRepay The amount of Asset Token to transfer
/// @param _shares The number of Borrow Shares the sender is repaying
/// @param _payer The address from which funds will be transferred
/// @param _borrower The borrower account which will be credited
function _repayAsset(
VaultAccount memory _totalBorrow,
uint128 _amountToRepay,
uint128 _shares,
address _payer,
address _borrower
) internal {
// Effects: Bookkeeping
_totalBorrow.amount -= _amountToRepay;
_totalBorrow.shares -= _shares;
// Effects: write to state
userBorrowShares[_borrower] -= _shares;
totalBorrow = _totalBorrow;
// Interactions
if (_payer != address(this)) {
assetContract.safeTransferFrom(_payer, address(this), _amountToRepay);
}
emit RepayAsset(_payer, _borrower, _amountToRepay, _shares);
}
/// @notice The ```repayAsset``` function allows the caller to pay down the debt for a given borrower.
/// @dev Caller must first invoke ```ERC20.approve()``` for the Asset Token contract
/// @param _shares The number of Borrow Shares which will be repaid by the call
/// @param _borrower The account for which the debt will be reduced
/// @return _amountToRepay The amount of Asset Tokens which were transferred in order to repay the Borrow Shares
function repayAsset(uint256 _shares, address _borrower) external nonReentrant returns (uint256 _amountToRepay) {
_addInterest();
VaultAccount memory _totalBorrow = totalBorrow;
_amountToRepay = _totalBorrow.toAmount(_shares, true);
_repayAsset(_totalBorrow, _amountToRepay.toUint128(), _shares.toUint128(), msg.sender, _borrower);
}
// ============================================================================================
// Functions: Liquidations
// ============================================================================================
/// @notice The ```Liquidate``` event is emitted when a liquidation occurs
/// @param _borrower The borrower account for which the liquidation occurred
/// @param _collateralForLiquidator The amount of Collateral Token transferred to the liquidator
/// @param _sharesToLiquidate The number of Borrow Shares the liquidator repaid on behalf of the borrower
/// @param _sharesToAdjust The number of Borrow Shares that were adjusted on liabilities and assets (a writeoff)
event Liquidate(
address indexed _borrower,
uint256 _collateralForLiquidator,
uint256 _sharesToLiquidate,
uint256 _amountLiquidatorToRepay,
uint256 _sharesToAdjust,
uint256 _amountToAdjust
);
/// @notice The ```liquidate``` function allows a third party to repay a borrower's debt if they have become insolvent
/// @dev Caller must invoke ```ERC20.approve``` on the Asset Token contract prior to calling ```Liquidate()```
/// @param _sharesToLiquidate The number of Borrow Shares repaid by the liquidator
/// @param _deadline The timestamp after which tx will revert
/// @param _borrower The account for which the repayment is credited and from whom collateral will be taken
/// @return _collateralForLiquidator The amount of Collateral Token transferred to the liquidator
function liquidate(
uint128 _sharesToLiquidate,
uint256 _deadline,
address _borrower
) external whenNotPaused nonReentrant approvedLender(msg.sender) returns (uint256 _collateralForLiquidator) {
if (block.timestamp > _deadline) revert PastDeadline(block.timestamp, _deadline);
_addInterest();
uint256 _exchangeRate = _updateExchangeRate();
if (_isSolvent(_borrower, _exchangeRate)) {
revert BorrowerSolvent();
}
// Read from state
VaultAccount memory _totalBorrow = totalBorrow;
uint256 _userCollateralBalance = userCollateralBalance[_borrower];
uint128 _borrowerShares = userBorrowShares[_borrower].toUint128();
// Prevent stack-too-deep
int256 _leftoverCollateral;
{
// Checks & Calculations
// Determine the liquidation amount in collateral units (i.e. how much debt is liquidator going to repay)
uint256 _liquidationAmountInCollateralUnits = ((_totalBorrow.toAmount(_sharesToLiquidate, false) *
_exchangeRate) / EXCHANGE_PRECISION);
// We first optimistically calculate the amount of collateral to give the liquidator based on the higher clean liquidation fee
// This fee only applies if the liquidator does a full liquidation
uint256 _optimisticCollateralForLiquidator = (_liquidationAmountInCollateralUnits *
(LIQ_PRECISION + cleanLiquidationFee)) / LIQ_PRECISION;
// Because interest accrues every block, _liquidationAmountInCollateralUnits from a few lines up is an ever increasing value
// This means that leftoverCollateral can occasionally go negative by a few hundred wei (cleanLiqFee premium covers this for liquidator)
_leftoverCollateral = (_userCollateralBalance.toInt256() - _optimisticCollateralForLiquidator.toInt256());
// If cleanLiquidation fee results in no leftover collateral, give liquidator all the collateral
// This will only be true when there liquidator is cleaning out the position
_collateralForLiquidator = _leftoverCollateral <= 0
? _userCollateralBalance
: (_liquidationAmountInCollateralUnits * (LIQ_PRECISION + dirtyLiquidationFee)) / LIQ_PRECISION;
}
// Calculated here for use during repayment, grouped with other calcs before effects start
uint128 _amountLiquidatorToRepay = (_totalBorrow.toAmount(_sharesToLiquidate, true)).toUint128();
// Determine if and how much debt to adjust
uint128 _sharesToAdjust;
{
uint128 _amountToAdjust;
if (_leftoverCollateral <= 0) {
// Determine if we need to adjust any shares
_sharesToAdjust = _borrowerShares - _sharesToLiquidate;
if (_sharesToAdjust > 0) {
// Write off bad debt
_amountToAdjust = (_totalBorrow.toAmount(_sharesToAdjust, false)).toUint128();
// Note: Ensure this memory struct will be passed to _repayAsset for write to state
_totalBorrow.amount -= _amountToAdjust;
// Effects: write to state
totalAsset.amount -= _amountToAdjust;
}
}
emit Liquidate(
_borrower,
_collateralForLiquidator,
_sharesToLiquidate,
_amountLiquidatorToRepay,
_sharesToAdjust,
_amountToAdjust
);
}
// Effects & Interactions
// NOTE: reverts if _shares > userBorrowShares
_repayAsset(
_totalBorrow,
_amountLiquidatorToRepay,
_sharesToLiquidate + _sharesToAdjust,
msg.sender,
_borrower
); // liquidator repays shares on behalf of borrower
// NOTE: reverts if _collateralForLiquidator > userCollateralBalance
// Collateral is removed on behalf of borrower and sent to liquidator
// NOTE: reverts if _collateralForLiquidator > userCollateralBalance
_removeCollateral(_collateralForLiquidator, msg.sender, _borrower);
}
// ============================================================================================
// Functions: Leverage
// ============================================================================================
/// @notice The ```LeveragedPosition``` event is emitted when a borrower takes out a new leveraged position
/// @param _borrower The account for which the debt is debited
/// @param _swapperAddress The address of the swapper which conforms the FraxSwap interface
/// @param _borrowAmount The amount of Asset Token to be borrowed to be borrowed
/// @param _borrowShares The number of Borrow Shares the borrower is credited
/// @param _initialCollateralAmount The amount of initial Collateral Tokens supplied by the borrower
/// @param _amountCollateralOut The amount of Collateral Token which was received for the Asset Tokens
event LeveragedPosition(
address indexed _borrower,
address _swapperAddress,
uint256 _borrowAmount,
uint256 _borrowShares,
uint256 _initialCollateralAmount,
uint256 _amountCollateralOut
);
/// @notice The ```leveragedPosition``` function allows a user to enter a leveraged borrow position with minimal upfront Collateral
/// @dev Caller must invoke ```ERC20.approve()``` on the Collateral Token contract prior to calling function
/// @param _swapperAddress The address of the whitelisted swapper to use to swap borrowed Asset Tokens for Collateral Tokens
/// @param _borrowAmount The amount of Asset Tokens borrowed
/// @param _initialCollateralAmount The initial amount of Collateral Tokens supplied by the borrower
/// @param _amountCollateralOutMin The minimum amount of Collateral Tokens to be received in exchange for the borrowed Asset Tokens
/// @param _path An array containing the addresses of ERC20 tokens to swap. Adheres to UniV2 style path params.
/// @return _totalCollateralBalance The total amount of Collateral Tokens added to a users account (initial + swap)
function leveragedPosition(
address _swapperAddress,
uint256 _borrowAmount,
uint256 _initialCollateralAmount,
uint256 _amountCollateralOutMin,
address[] memory _path
)
external
isNotPastMaturity
nonReentrant
whenNotPaused
approvedBorrower
isSolvent(msg.sender)
returns (uint256 _totalCollateralBalance)
{
_addInterest();
_updateExchangeRate();
IERC20 _assetContract = assetContract;
IERC20 _collateralContract = collateralContract;
if (!swappers[_swapperAddress]) {
revert BadSwapper();
}
if (_path[0] != address(_assetContract)) {
revert InvalidPath(address(_assetContract), _path[0]);
}
if (_path[_path.length - 1] != address(_collateralContract)) {
revert InvalidPath(address(_collateralContract), _path[_path.length - 1]);
}
// Add initial collateral
if (_initialCollateralAmount > 0) {
_addCollateral(msg.sender, _initialCollateralAmount, msg.sender);
}
// Debit borrowers account
// setting recipient to address(this) means no transfer will happen
uint256 _borrowShares = _borrowAsset(_borrowAmount.toUint128(), address(this));
// Interactions
_assetContract.approve(_swapperAddress, _borrowAmount);
// Even though swappers are trusted, we verify the balance before and after swap
uint256 _initialCollateralBalance = _collateralContract.balanceOf(address(this));
ISwapper(_swapperAddress).swapExactTokensForTokens(
_borrowAmount,
_amountCollateralOutMin,
_path,
address(this),
block.timestamp
);
uint256 _finalCollateralBalance = _collateralContract.balanceOf(address(this));
// Note: VIOLATES CHECKS-EFFECTS-INTERACTION pattern, make sure function is NONREENTRANT
// Effects: bookkeeping & write to state
uint256 _amountCollateralOut = _finalCollateralBalance - _initialCollateralBalance;
if (_amountCollateralOut < _amountCollateralOutMin) {
revert SlippageTooHigh(_amountCollateralOutMin, _amountCollateralOut);
}
// address(this) as _sender means no transfer occurs as the pair has already received the collateral during swap
_addCollateral(address(this), _amountCollateralOut, msg.sender);
_totalCollateralBalance = _initialCollateralAmount + _amountCollateralOut;
emit LeveragedPosition(
msg.sender,
_swapperAddress,
_borrowAmount,
_borrowShares,
_initialCollateralAmount,
_amountCollateralOut
);
}
/// @notice The ```RepayAssetWithCollateral``` event is emitted whenever ```repayAssetWithCollateral()``` is invoked
/// @param _borrower The borrower account for which the repayment is taking place
/// @param _swapperAddress The address of the whitelisted swapper to use for token swaps
/// @param _collateralToSwap The amount of Collateral Token to swap and use for repayment
/// @param _amountAssetOut The amount of Asset Token which was repaid
/// @param _sharesRepaid The number of Borrow Shares which were repaid
event RepayAssetWithCollateral(
address indexed _borrower,
address _swapperAddress,
uint256 _collateralToSwap,
uint256 _amountAssetOut,
uint256 _sharesRepaid
);
/// @notice The ```repayAssetWithCollateral``` function allows a borrower to repay their debt using existing collateral in contract
/// @param _swapperAddress The address of the whitelisted swapper to use for token swaps
/// @param _collateralToSwap The amount of Collateral Tokens to swap for Asset Tokens
/// @param _amountAssetOutMin The minimum amount of Asset Tokens to receive during the swap
/// @param _path An array containing the addresses of ERC20 tokens to swap. Adheres to UniV2 style path params.
/// @return _amountAssetOut The amount of Asset Tokens received for the Collateral Tokens, the amount the borrowers account was credited
function repayAssetWithCollateral(
address _swapperAddress,
uint256 _collateralToSwap,
uint256 _amountAssetOutMin,
address[] calldata _path
) external nonReentrant isSolvent(msg.sender) returns (uint256 _amountAssetOut) {
_addInterest();
_updateExchangeRate();
IERC20 _assetContract = assetContract;
IERC20 _collateralContract = collateralContract;
if (!swappers[_swapperAddress]) {
revert BadSwapper();
}
if (_path[0] != address(_collateralContract)) {
revert InvalidPath(address(_collateralContract), _path[0]);
}
if (_path[_path.length - 1] != address(_assetContract)) {
revert InvalidPath(address(_assetContract), _path[_path.length - 1]);
}
// Effects: bookkeeping & write to state
// Debit users collateral balance in preparation for swap, setting _recipient to address(this) means no transfer occurs
_removeCollateral(_collateralToSwap, address(this), msg.sender);
// Interactions
_collateralContract.approve(_swapperAddress, _collateralToSwap);
// Even though swappers are trusted, we verify the balance before and after swap
uint256 _initialAssetBalance = _assetContract.balanceOf(address(this));
ISwapper(_swapperAddress).swapExactTokensForTokens(
_collateralToSwap,
_amountAssetOutMin,
_path,
address(this),
block.timestamp
);
uint256 _finalAssetBalance = _assetContract.balanceOf(address(this));
// Note: VIOLATES CHECKS-EFFECTS-INTERACTION pattern, make sure function is NONREENTRANT
// Effects: bookkeeping
_amountAssetOut = _finalAssetBalance - _initialAssetBalance;
if (_amountAssetOut < _amountAssetOutMin) {
revert SlippageTooHigh(_amountAssetOutMin, _amountAssetOut);
}
VaultAccount memory _totalBorrow = totalBorrow;
uint256 _sharesToRepay = _totalBorrow.toShares(_amountAssetOut, false);
// Effects: write to state
// Note: setting _payer to address(this) means no actual transfer will occur. Contract already has funds
_repayAsset(_totalBorrow, _amountAssetOut.toUint128(), _sharesToRepay.toUint128(), address(this), msg.sender);
emit RepayAssetWithCollateral(msg.sender, _swapperAddress, _collateralToSwap, _amountAssetOut, _sharesToRepay);
}
}
// SPDX-License-Identifier: ISC
pragma solidity ^0.8.16;
struct VaultAccount {
uint128 amount; // Total amount, analogous to market cap
uint128 shares; // Total shares, analogous to shares outstanding
}
/// @title VaultAccount Library
/// @author Drake Evans (Frax Finance) github.com/drakeevans, modified from work by @Boring_Crypto github.com/boring_crypto
/// @notice Provides a library for use with the VaultAccount struct, provides convenient math implementations
/// @dev Uses uint128 to save on storage
library VaultAccountingLibrary {
/// @notice Calculates the shares value in relationship to `amount` and `total`
/// @dev Given an amount, return the appropriate number of shares
function toShares(
VaultAccount memory total,
uint256 amount,
bool roundUp
) internal pure returns (uint256 shares) {
if (total.amount == 0) {
shares = amount;
} else {
shares = (amount * total.shares) / total.amount;
if (roundUp && (shares * total.amount) / total.shares < amount) {
shares = shares + 1;
}
}
}
/// @notice Calculates the amount value in relationship to `shares` and `total`
/// @dev Given a number of shares, returns the appropriate amount
function toAmount(
VaultAccount memory total,
uint256 shares,
bool roundUp
) internal pure returns (uint256 amount) {
if (total.shares == 0) {
amount = shares;
} else {
amount = (shares * total.amount) / total.shares;
if (roundUp && (amount * total.shares) / total.amount < shares) {
amount = amount + 1;
}
}
}
}
// SPDX-License-Identifier: ISC
pragma solidity ^0.8.16;
import "@openzeppelin/contracts/interfaces/IERC20.sol";
import { SafeERC20 as OZSafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
// solhint-disable avoid-low-level-calls
// solhint-disable max-line-length
/// @title SafeERC20 provides helper functions for safe transfers as well as safe metadata access
/// @author Library originally written by @Boring_Crypto github.com/boring_crypto, modified by Drake Evans (Frax Finance) github.com/drakeevans
/// @dev original: https://github.com/boringcrypto/BoringSolidity/blob/fed25c5d43cb7ce20764cd0b838e21a02ea162e9/contracts/libraries/BoringERC20.sol
library SafeERC20 {
bytes4 private constant SIG_SYMBOL = 0x95d89b41; // symbol()
bytes4 private constant SIG_NAME = 0x06fdde03; // name()
bytes4 private constant SIG_DECIMALS = 0x313ce567; // decimals()
function returnDataToString(bytes memory data) internal pure returns (string memory) {
if (data.length >= 64) {
return abi.decode(data, (string));
} else if (data.length == 32) {
uint8 i = 0;
while (i < 32 && data[i] != 0) {
i++;
}
bytes memory bytesArray = new bytes(i);
for (i = 0; i < 32 && data[i] != 0; i++) {
bytesArray[i] = data[i];
}
return string(bytesArray);
} else {
return "???";
}
}
/// @notice Provides a safe ERC20.symbol version which returns '???' as fallback string.
/// @param token The address of the ERC-20 token contract.
/// @return (string) Token symbol.
function safeSymbol(IERC20 token) internal view returns (string memory) {
(bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_SYMBOL));
return success ? returnDataToString(data) : "???";
}
/// @notice Provides a safe ERC20.name version which returns '???' as fallback string.
/// @param token The address of the ERC-20 token contract.
/// @return (string) Token name.
function safeName(IERC20 token) internal view returns (string memory) {
(bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_NAME));
return success ? returnDataToString(data) : "???";
}
/// @notice Provides a safe ERC20.decimals version which returns '18' as fallback value.
/// @param token The address of the ERC-20 token contract.
/// @return (uint8) Token decimals.
function safeDecimals(IERC20 token) internal view returns (uint8) {
(bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_DECIMALS));
return success && data.length == 32 ? abi.decode(data, (uint8)) : 18;
}
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
OZSafeERC20.safeTransfer(token, to, value);
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
OZSafeERC20.safeTransferFrom(token, from, to, value);
}
}
// SPDX-License-Identifier: ISC
pragma solidity >=0.8.16;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
interface IERC4626 is IERC20, IERC20Metadata {
event Deposit(address indexed caller, address indexed owner, uint256 assets, uint256 shares);
event Withdraw(
address indexed caller,
address indexed receiver,
address indexed owner,
uint256 assets,
uint256 shares
);
function asset() external view returns (address);
function convertToAssets(uint256 shares) external view returns (uint256);
function convertToShares(uint256 assets) external view returns (uint256);
function maxDeposit(address) external view returns (uint256);
function maxMint(address) external view returns (uint256);
function maxRedeem(address owner) external view returns (uint256);
function maxWithdraw(address owner) external view returns (uint256);
function previewDeposit(uint256 assets) external view returns (uint256);
function previewMint(uint256 shares) external view returns (uint256);
function previewRedeem(uint256 shares) external view returns (uint256);
function previewWithdraw(uint256 assets) external view returns (uint256);
function totalAssets() external view returns (uint256);
function mint(uint256 shares, address receiver) external returns (uint256 assets);
function deposit(uint256 assets, address receiver) external returns (uint256 shares);
function redeem(
uint256 shares,
address receiver,
address owner
) external returns (uint256 assets);
function withdraw(
uint256 assets,
address receiver,
address owner
) external returns (uint256 shares);
}
// SPDX-License-Identifier: ISC
pragma solidity >=0.8.16;
interface IFraxlendWhitelist {
function fraxlendDeployerWhitelist(address) external view returns (bool);
function oracleContractWhitelist(address) external view returns (bool);
function owner() external view returns (address);
function rateContractWhitelist(address) external view returns (bool);
function renounceOwnership() external;
function setFraxlendDeployerWhitelist(address[] calldata _addresses, bool _bool) external;
function setOracleContractWhitelist(address[] calldata _addresses, bool _bool) external;
function setRateContractWhitelist(address[] calldata _addresses, bool _bool) external;
function transferOwnership(address newOwner) external;
}
// SPDX-License-Identifier: ISC
pragma solidity >=0.8.16;
interface IRateCalculator {
function name() external pure returns (string memory);
function requireValidInitData(bytes calldata _initData) external pure;
function getConstants() external pure returns (bytes memory _calldata);
function getNewRate(bytes calldata _data, bytes calldata _initData) external pure returns (uint64 _newRatePerSec);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.8.16;
interface ISwapper {
function swapExactTokensForTokens(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external returns (uint256[] memory amounts);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.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 {ERC20PresetMinterPauser}.
*
* 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 Contracts guidelines: functions revert
* instead 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, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override 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 this function is
* overridden;
*
* 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 virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, 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}.
*
* NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
* `transferFrom`. This is semantically equivalent to an infinite approval.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, 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}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(
address from,
address to,
uint256 amount
) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
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) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, spender) + 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) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This 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:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
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");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
}
_balances[to] += amount;
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, 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:
*
* - `account` 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 += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), 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);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This 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 Updates `owner` s allowance for `spender` based on spent `amount`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
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);
}
}
}
/**
* @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 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:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/Pausable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Contract module which allows children to implement an emergency stop
* mechanism that can be triggered by an authorized account.
*
* This module is used through inheritance. It will make available the
* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
* the functions of your contract. Note that they will not be pausable by
* simply including this module, only once the modifiers are put in place.
*/
abstract contract Pausable is Context {
/**
* @dev Emitted when the pause is triggered by `account`.
*/
event Paused(address account);
/**
* @dev Emitted when the pause is lifted by `account`.
*/
event Unpaused(address account);
bool private _paused;
/**
* @dev Initializes the contract in unpaused state.
*/
constructor() {
_paused = false;
}
/**
* @dev Returns true if the contract is paused, and false otherwise.
*/
function paused() public view virtual returns (bool) {
return _paused;
}
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*
* Requirements:
*
* - The contract must not be paused.
*/
modifier whenNotPaused() {
require(!paused(), "Pausable: paused");
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*
* Requirements:
*
* - The contract must be paused.
*/
modifier whenPaused() {
require(paused(), "Pausable: not paused");
_;
}
/**
* @dev Triggers stopped state.
*
* Requirements:
*
* - The contract must not be paused.
*/
function _pause() internal virtual whenNotPaused {
_paused = true;
emit Paused(_msgSender());
}
/**
* @dev Returns to normal state.
*
* Requirements:
*
* - The contract must be paused.
*/
function _unpause() internal virtual whenPaused {
_paused = false;
emit Unpaused(_msgSender());
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
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() {
_transferOwnership(_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 {
_transferOwnership(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");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/SafeCast.sol)
pragma solidity ^0.8.0;
/**
* @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
* checks.
*
* Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
* easily result in undesired exploitation or bugs, since developers usually
* assume that overflows raise errors. `SafeCast` restores this intuition by
* reverting the transaction when such 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.
*
* Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
* all math on `uint256` and `int256` and then downcasting.
*/
library SafeCast {
/**
* @dev Returns the downcasted uint224 from uint256, reverting on
* overflow (when the input is greater than largest uint224).
*
* Counterpart to Solidity's `uint224` operator.
*
* Requirements:
*
* - input must fit into 224 bits
*/
function toUint224(uint256 value) internal pure returns (uint224) {
require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
return uint224(value);
}
/**
* @dev Returns the downcasted uint128 from uint256, reverting on
* overflow (when the input is greater than largest uint128).
*
* Counterpart to Solidity's `uint128` operator.
*
* Requirements:
*
* - input must fit into 128 bits
*/
function toUint128(uint256 value) internal pure returns (uint128) {
require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
return uint128(value);
}
/**
* @dev Returns the downcasted uint96 from uint256, reverting on
* overflow (when the input is greater than largest uint96).
*
* Counterpart to Solidity's `uint96` operator.
*
* Requirements:
*
* - input must fit into 96 bits
*/
function toUint96(uint256 value) internal pure returns (uint96) {
require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
return uint96(value);
}
/**
* @dev Returns the downcasted uint64 from uint256, reverting on
* overflow (when the input is greater than largest uint64).
*
* Counterpart to Solidity's `uint64` operator.
*
* Requirements:
*
* - input must fit into 64 bits
*/
function toUint64(uint256 value) internal pure returns (uint64) {
require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
return uint64(value);
}
/**
* @dev Returns the downcasted uint32 from uint256, reverting on
* overflow (when the input is greater than largest uint32).
*
* Counterpart to Solidity's `uint32` operator.
*
* Requirements:
*
* - input must fit into 32 bits
*/
function toUint32(uint256 value) internal pure returns (uint32) {
require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
return uint32(value);
}
/**
* @dev Returns the downcasted uint16 from uint256, reverting on
* overflow (when the input is greater than largest uint16).
*
* Counterpart to Solidity's `uint16` operator.
*
* Requirements:
*
* - input must fit into 16 bits
*/
function toUint16(uint256 value) internal pure returns (uint16) {
require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
return uint16(value);
}
/**
* @dev Returns the downcasted uint8 from uint256, reverting on
* overflow (when the input is greater than largest uint8).
*
* Counterpart to Solidity's `uint8` operator.
*
* Requirements:
*
* - input must fit into 8 bits.
*/
function toUint8(uint256 value) internal pure returns (uint8) {
require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
return uint8(value);
}
/**
* @dev Converts a signed int256 into an unsigned uint256.
*
* Requirements:
*
* - input must be greater than or equal to 0.
*/
function toUint256(int256 value) internal pure returns (uint256) {
require(value >= 0, "SafeCast: value must be positive");
return uint256(value);
}
/**
* @dev Returns the downcasted int128 from int256, reverting on
* overflow (when the input is less than smallest int128 or
* greater than largest int128).
*
* Counterpart to Solidity's `int128` operator.
*
* Requirements:
*
* - input must fit into 128 bits
*
* _Available since v3.1._
*/
function toInt128(int256 value) internal pure returns (int128) {
require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
return int128(value);
}
/**
* @dev Returns the downcasted int64 from int256, reverting on
* overflow (when the input is less than smallest int64 or
* greater than largest int64).
*
* Counterpart to Solidity's `int64` operator.
*
* Requirements:
*
* - input must fit into 64 bits
*
* _Available since v3.1._
*/
function toInt64(int256 value) internal pure returns (int64) {
require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
return int64(value);
}
/**
* @dev Returns the downcasted int32 from int256, reverting on
* overflow (when the input is less than smallest int32 or
* greater than largest int32).
*
* Counterpart to Solidity's `int32` operator.
*
* Requirements:
*
* - input must fit into 32 bits
*
* _Available since v3.1._
*/
function toInt32(int256 value) internal pure returns (int32) {
require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
return int32(value);
}
/**
* @dev Returns the downcasted int16 from int256, reverting on
* overflow (when the input is less than smallest int16 or
* greater than largest int16).
*
* Counterpart to Solidity's `int16` operator.
*
* Requirements:
*
* - input must fit into 16 bits
*
* _Available since v3.1._
*/
function toInt16(int256 value) internal pure returns (int16) {
require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
return int16(value);
}
/**
* @dev Returns the downcasted int8 from int256, reverting on
* overflow (when the input is less than smallest int8 or
* greater than largest int8).
*
* Counterpart to Solidity's `int8` operator.
*
* Requirements:
*
* - input must fit into 8 bits.
*
* _Available since v3.1._
*/
function toInt8(int256 value) internal pure returns (int8) {
require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
return int8(value);
}
/**
* @dev Converts an unsigned uint256 into a signed int256.
*
* Requirements:
*
* - input must be less than or equal to maxInt256.
*/
function toInt256(uint256 value) internal pure returns (int256) {
// Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
return int256(value);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
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
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC20.sol)
pragma solidity ^0.8.0;
import "../token/ERC20/IERC20.sol";
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
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
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @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
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 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);
}
}
}
}