ReentrancyGuard

ReentrancyGuard based on OpenZeppelin implementation. https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.8/contracts/security/ReentrancyGuard.sol

REENTRANCY_NOT_ENTERED

uint8 REENTRANCY_NOT_ENTERED

REENTRANCY_ENTERED

uint8 REENTRANCY_ENTERED

constructor

constructor() internal

_checkReentrancy

function _checkReentrancy() internal

checks that no reentrancy occurs, reverts if so. Calling the method in the modifier reduces bytecode size as modifiers are inlined into bytecode

nonReentrant

modifier nonReentrant()

Prevents a contract from calling itself, directly or indirectly. See OpenZeppelin implementation for more info

fTokenCore

internal methods for fToken contracts

_getLiquidityExchangePrice

function _getLiquidityExchangePrice() internal view returns (uint256 supplyExchangePrice_)

Gets current (updated) Liquidity supply exchange price for the underyling asset

_getLiquidityBalance

function _getLiquidityBalance() internal view returns (uint256 balance_)

Gets current Liquidity supply balance of address(this) for the underyling asset

_getLiquidityUnderlyingBalance

function _getLiquidityUnderlyingBalance() internal view virtual returns (uint256)

Gets current Liquidity underlying token balance

_getLiquidityWithdrawable

function _getLiquidityWithdrawable() internal view returns (uint256 withdrawalLimit_)

_Gets current withdrawable amount at Liquidity withdrawalLimit_ (withdrawal limit or balance)._

_calculateNewTokenExchangePrice

function _calculateNewTokenExchangePrice(uint256 newLiquidityExchangePrice_) internal view returns (uint256 newTokenExchangePrice_, bool rewardsEnded_)

_Calculates new token exchange price based on the current liquidity exchange price newLiquidityExchangePrice_ and rewards rate._

Parameters

_updateRates

function _updateRates(uint256 liquidityExchangePrice_, bool forceUpdateStorage_) internal returns (uint256 tokenExchangePrice_)

calculates new exchange prices, updates values in storage and returns new tokenExchangePrice (with reward rates)

_splitSignature

function _splitSignature(bytes sig) internal pure returns (uint8 v, bytes32 r, bytes32 s)

splits a bytes signature sig into v, r, s. Taken from https://docs.soliditylang.org/en/v0.8.17/solidity-by-example.html

_depositToLiquidity

function _depositToLiquidity(uint256 assets_, bytes liquidityCallbackData_) internal virtual returns (uint256 exchangePrice_)

_Deposit assets_ amount of tokens to Liquidity_

Parameters

Return Values

_withdrawFromLiquidity

function _withdrawFromLiquidity(uint256 assets_, address receiver_) internal virtual returns (uint256 exchangePrice_)

_Withdraw assets_amount of tokens from Liquidity directly toreceiver**

Parameters

Return Values

_executeDeposit

function _executeDeposit(uint256 assets_, address receiver_, bytes liquidityCallbackData_) internal virtual returns (uint256 sharesMinted_)

_deposits assets_into liquidity and mints shares forreceiver*. Returns amount of sharesMinted*._

_executeWithdraw

function _executeWithdraw(uint256 assets_, address receiver_, address owner_) internal virtual returns (uint256 sharesBurned_)

_withdraws assets_from liquidity toreceiver*and burns shares fromowner*. Returns amount of sharesBurned*. requires nonReentrant! modifier on calling method otherwise ERC777s could reenter!*

fTokenViews

fToken view methods. Implements view methods for ERC4626 compatibility

getData

function getData() public view returns (contract IFluidLiquidity liquidity_, contract IFluidLendingFactory lendingFactory_, contract IFluidLendingRewardsRateModel lendingRewardsRateModel_, contract IAllowanceTransfer permit2_, address rebalancer_, bool rewardsActive_, uint256 liquidityBalance_, uint256 liquidityExchangePrice_, uint256 tokenExchangePrice_)

returns config, rewards and exchange prices data in a single view method.

Return Values

asset

function asset() public view virtual returns (address)

_Returns the address of the underlying token used for the Vault for accounting, depositing, and withdrawing.

• MUST be an ERC-20 token contract.
• MUST NOT revert._

totalAssets

function totalAssets() public view virtual returns (uint256)

_Returns the total amount of the underlying asset that is “managed” by Vault.

• SHOULD include any compounding that occurs from yield.
• MUST be inclusive of any fees that are charged against assets in the Vault.
• MUST NOT revert._

convertToShares

function convertToShares(uint256 assets_) public view virtual returns (uint256)

_Returns the amount of shares that the Vault would exchange for the amount of assets provided, in an ideal scenario where all the conditions are met.

• MUST NOT be inclusive of any fees that are charged against assets in the Vault.
• MUST NOT show any variations depending on the caller.
• MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
• MUST NOT revert.

NOTE: This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and from._

convertToAssets

function convertToAssets(uint256 shares_) public view virtual returns (uint256)

_Returns the amount of assets that the Vault would exchange for the amount of shares provided, in an ideal scenario where all the conditions are met.

• MUST NOT be inclusive of any fees that are charged against assets in the Vault.
• MUST NOT show any variations depending on the caller.
• MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
• MUST NOT revert.

NOTE: This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and from._

previewDeposit

function previewDeposit(uint256 assets_) public view virtual returns (uint256)

returned amount might be slightly different from actual amount at execution.

_Allows an on-chain or off-chain user to simulate the effects of their deposit at the current block, given current on-chain conditions.

• MUST return as close to and no more than the exact amount of Vault shares that would be minted in a deposit call in the same transaction. I.e. deposit should return the same or more shares as previewDeposit if called in the same transaction.
• MUST NOT account for deposit limits like those returned from maxDeposit and should always act as though the deposit would be accepted, regardless if the user has enough tokens approved, etc.
• MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
• MUST NOT revert.

NOTE: any unfavorable discrepancy between convertToShares and previewDeposit SHOULD be considered slippage in share price or some other type of condition, meaning the depositor will lose assets by depositing._

previewMint

function previewMint(uint256 shares_) public view virtual returns (uint256)

_Allows an on-chain or off-chain user to simulate the effects of their mint at the current block, given current on-chain conditions.

• MUST return as close to and no fewer than the exact amount of assets that would be deposited in a mint call in the same transaction. I.e. mint should return the same or fewer assets as previewMint if called in the same transaction.
• MUST NOT account for mint limits like those returned from maxMint and should always act as though the mint would be accepted, regardless if the user has enough tokens approved, etc.
• MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
• MUST NOT revert.

NOTE: any unfavorable discrepancy between convertToAssets and previewMint SHOULD be considered slippage in share price or some other type of condition, meaning the depositor will lose assets by minting._

previewWithdraw

function previewWithdraw(uint256 assets_) public view virtual returns (uint256)

_Allows an on-chain or off-chain user to simulate the effects of their withdrawal at the current block, given current on-chain conditions.

• MUST return as close to and no fewer than the exact amount of Vault shares that would be burned in a withdraw call in the same transaction. I.e. withdraw should return the same or fewer shares as previewWithdraw if called in the same transaction.
• MUST NOT account for withdrawal limits like those returned from maxWithdraw and should always act as though the withdrawal would be accepted, regardless if the user has enough shares, etc.
• MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
• MUST NOT revert.

NOTE: any unfavorable discrepancy between convertToShares and previewWithdraw SHOULD be considered slippage in share price or some other type of condition, meaning the depositor will lose assets by depositing._

previewRedeem

function previewRedeem(uint256 shares_) public view virtual returns (uint256)

returned amount might be slightly different from actual amount at execution.

_Allows an on-chain or off-chain user to simulate the effects of their redeemption at the current block, given current on-chain conditions.

• MUST return as close to and no more than the exact amount of assets that would be withdrawn in a redeem call in the same transaction. I.e. redeem should return the same or more assets as previewRedeem if called in the same transaction.
• MUST NOT account for redemption limits like those returned from maxRedeem and should always act as though the redemption would be accepted, regardless if the user has enough shares, etc.
• MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
• MUST NOT revert.

NOTE: any unfavorable discrepancy between convertToAssets and previewRedeem SHOULD be considered slippage in share price or some other type of condition, meaning the depositor will lose assets by redeeming._

maxDeposit

function maxDeposit(address) public view virtual returns (uint256)

_Returns the maximum amount of the underlying asset that can be deposited into the Vault for the receiver, through a deposit call.

• MUST return a limited value if receiver is subject to some deposit limit.
• MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of assets that may be deposited.
• MUST NOT revert._

maxMint

function maxMint(address) public view virtual returns (uint256)

_Returns the maximum amount of the Vault shares that can be minted for the receiver, through a mint call.

• MUST return a limited value if receiver is subject to some mint limit.
• MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of shares that may be minted.
• MUST NOT revert._

maxWithdraw

function maxWithdraw(address owner_) public view virtual returns (uint256)

_Returns the maximum amount of the underlying asset that can be withdrawn from the owner balance in the Vault, through a withdraw call.

• MUST return a limited value if owner is subject to some withdrawal limit or timelock.
• MUST NOT revert._

maxRedeem

function maxRedeem(address owner_) public view virtual returns (uint256)

_Returns the maximum amount of Vault shares that can be redeemed from the owner balance in the Vault, through a redeem call.

• MUST return a limited value if owner is subject to some withdrawal limit or timelock.
• MUST return balanceOf(owner) if owner is not subject to any withdrawal limit or timelock.
• MUST NOT revert._

minDeposit

function minDeposit() public view returns (uint256)

returns minimum amount required for deposit (rounded up)

fTokenAdmin

fToken admin related methods. fToken admins are Lending Factory auths. Possible actions are updating rewards, funding rewards, and rescuing any stuck funds (fToken contract itself never holds any funds).

_checkIsLendingFactoryAuth

function _checkIsLendingFactoryAuth() internal view

checks if msg.sender is an allowed auth at LendingFactory. internal method instead of modifier to reduce bytecode size.

updateRewards

function updateRewards(contract IFluidLendingRewardsRateModel rewardsRateModel_) external

updates the rewards rate model contract. Only callable by LendingFactory auths.

Parameters

rebalance

function rebalance() external payable virtual returns (uint256 assets_)

Balances out the difference between fToken supply at Liquidity vs totalAssets(). Deposits underlying from rebalancer address into Liquidity but doesn't mint any shares -> thus making deposit available as rewards. Only callable by rebalancer.

Return Values

updateRebalancer

function updateRebalancer(address newRebalancer_) public

Updates the rebalancer address (ReserveContract). Only callable by LendingFactory auths.

updateRates

function updateRates() public returns (uint256 tokenExchangePrice_, uint256 liquidityExchangePrice_)

gets the liquidity exchange price of the underlying asset, calculates the updated exchange price (with reward rates) and writes those values to storage. Callable by anyone.

Return Values

rescueFunds

function rescueFunds(address token_) external virtual

sends any potentially stuck funds to Liquidity contract. Only callable by LendingFactory auths.

fTokenActions

fToken public executable actions: deposit, mint, mithdraw and redeem. All actions are optionally also available with an additional param to limit the maximum slippage, e.g. maximum assets used for minting x amount of shares.

_revertIfBelowMinAmountOut

function _revertIfBelowMinAmountOut(uint256 amount_, uint256 minAmountOut_) internal pure

_reverts if amount_is <minAmountOut*. Used to reduce bytecode size.*

_revertIfAboveMaxAmount

function _revertIfAboveMaxAmount(uint256 amount_, uint256 maxAmount_) internal pure

_reverts if amount_is >maxAmount*. Used to reduce bytecode size.*

deposit

function deposit(uint256 assets_, address receiver_) public virtual returns (uint256 shares_)

If assets_ equals uint256.max then the whole balance of msg.sender is deposited. assets_ must at least be minDeposit() amount; reverts fToken__DepositInsignificant() if not. Recommended to use deposit() with a minAmountOut_ param instead to set acceptable limit.

_Mints shares Vault shares to receiver by depositing exactly amount of underlying tokens.

• MUST emit the Deposit event.
• MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the deposit execution, and are accounted for during deposit.
• MUST revert if all of assets cannot be deposited (due to deposit limit being reached, slippage, the user not approving enough underlying tokens to the Vault contract, etc).

NOTE: most implementations will require pre-approval of the Vault with the Vault’s underlying asset token._

Return Values

deposit

function deposit(uint256 assets_, address receiver_, uint256 minAmountOut_) external returns (uint256 shares_)

same as {fToken-deposit} but with an additional setting for minimum output amount. reverts with fToken__MinAmountOut() if minAmountOut_ of shares is not reached

mint

function mint(uint256 shares_, address receiver_) public virtual returns (uint256 assets_)

If shares_ equals uint256.max then the whole balance of msg.sender is deposited. shares_ must at least be minMint() amount; reverts fToken__DepositInsignificant() if not. Note there might be tiny inaccuracies between requested shares_ and actually received shares amount. Recommended to use deposit() over mint because it is more gas efficient and less likely to revert. Recommended to use mint() with a minAmountOut_ param instead to set acceptable limit.

_Mints exactly shares Vault shares to receiver by depositing amount of underlying tokens.

• MUST emit the Deposit event.
• MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the mint execution, and are accounted for during mint.
• MUST revert if all of shares cannot be minted (due to deposit limit being reached, slippage, the user not approving enough underlying tokens to the Vault contract, etc).

NOTE: most implementations will require pre-approval of the Vault with the Vault’s underlying asset token._

Return Values

mint

function mint(uint256 shares_, address receiver_, uint256 maxAssets_) external returns (uint256 assets_)

same as {fToken-mint} but with an additional setting for maximum assets input amount. reverts with fToken__MaxAmount() if maxAssets_ of assets is surpassed to mint shares_.

withdraw

function withdraw(uint256 assets_, address receiver_, address owner_) public virtual returns (uint256 shares_)

If assets_ equals uint256.max then the whole fToken balance of owner_ is withdrawn. This does not consider withdrawal limit at Liquidity so best to check with maxWithdraw() before. Note there might be tiny inaccuracies between requested assets_ and actually received assets amount. Recommended to use withdraw() with a minAmountOut_ param instead to set acceptable limit.

_Burns shares from owner and sends exactly assets of underlying tokens to receiver.

• MUST emit the Withdraw event.
• MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the withdraw execution, and are accounted for during withdraw.
• MUST revert if all of assets cannot be withdrawn (due to withdrawal limit being reached, slippage, the owner not having enough shares, etc).

Note that some implementations will require pre-requesting to the Vault before a withdrawal may be performed. Those methods should be performed separately._

Return Values

withdraw

function withdraw(uint256 assets_, address receiver_, address owner_, uint256 maxSharesBurn_) external returns (uint256 shares_)

same as {fToken-withdraw} but with an additional setting for maximum shares burned. reverts with fToken__MaxAmount() if maxSharesBurn_ of shares burned is surpassed.

redeem

function redeem(uint256 shares_, address receiver_, address owner_) public virtual returns (uint256 assets_)

If shares_ equals uint256.max then the whole balance of owner_ is withdrawn.This does not consider withdrawal limit at Liquidity so best to check with maxRedeem() before. Recommended to use withdraw() over redeem because it is more gas efficient and can set specific amount. Recommended to use redeem() with a minAmountOut_ param instead to set acceptable limit.

_Burns exactly shares from owner and sends assets of underlying tokens to receiver.

• MUST emit the Withdraw event.
• MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the redeem execution, and are accounted for during redeem.
• MUST revert if all of shares cannot be redeemed (due to withdrawal limit being reached, slippage, the owner not having enough shares, etc).

NOTE: some implementations will require pre-requesting to the Vault before a withdrawal may be performed. Those methods should be performed separately._

Return Values

redeem

function redeem(uint256 shares_, address receiver_, address owner_, uint256 minAmountOut_) external returns (uint256 assets_)

same as {fToken-redeem} but with an additional setting for minimum output amount. reverts with fToken__MinAmountOut() if minAmountOut_ of assets is not reached.

fTokenEIP2612Withdrawals

fTokens support EIP-2612 permit approvals via signature so this contract implements withdrawals (withdraw / redeem) with signature used for approval of the fToken shares.

_allowViaPermitEIP2612

function _allowViaPermitEIP2612(address owner_, uint256 sharesToPermit_, uint256 deadline_, bytes signature_) internal

_creates sharesToPermit_allowance forowner*via EIP2612deadline*andsignature**

withdrawWithSignature

function withdrawWithSignature(uint256 sharesToPermit_, uint256 assets_, address receiver_, address owner_, uint256 maxSharesBurn_, uint256 deadline_, bytes signature_) external virtual returns (uint256 shares_)

withdraw amount of assets_ with ERC-2612 permit signature for fToken approval. owner_ signs ERC-2612 permit signature_ to give allowance of fTokens to msg.sender. Note there might be tiny inaccuracies between requested assets_ and actually received assets amount. allowance via signature (sharesToPermit_) should cover previewWithdraw(assets_) plus a little buffer to avoid revert. Inherent trust assumption that msg.sender will set receiver_ and maxSharesBurn_ as owner_ intends (which is always the case when giving allowance to some spender).

Parameters

Return Values

redeemWithSignature

function redeemWithSignature(uint256 shares_, address receiver_, address owner_, uint256 minAmountOut_, uint256 deadline_, bytes signature_) external virtual returns (uint256 assets_)

redeem amount of shares_ with ERC-2612 permit signature for fToken approval. owner_ signs ERC-2612 permit signature_ to give allowance of fTokens to msg.sender. Note there might be tiny inaccuracies between requested shares_ to redeem and actually burned shares. allowance via signature must cover shares_ plus a tiny buffer. Inherent trust assumption that msg.sender will set receiver_ and minAmountOut_ as owner_ intends (which is always the case when giving allowance to some spender). Recommended to use withdraw() over redeem because it is more gas efficient and can set specific amount.

Parameters

Return Values

fTokenEIP2612Deposits

implements fTokens support for deposit / mint via EIP-2612 permit.

methods revert if underlying asset does not support EIP-2612.

depositWithSignatureEIP2612

function depositWithSignatureEIP2612(uint256 assets_, address receiver_, uint256 minAmountOut_, uint256 deadline_, bytes signature_) external returns (uint256 shares_)

deposit assets_ amount with EIP-2612 Permit2 signature for underlying asset approval. IMPORTANT: This will revert if the underlying asset() does not support EIP-2612. reverts with fToken__MinAmountOut() if minAmountOut_ of shares is not reached. assets_ must at least be minDeposit() amount; reverts fToken__DepositInsignificant() if not.

Parameters

Return Values

mintWithSignatureEIP2612

function mintWithSignatureEIP2612(uint256 shares_, address receiver_, uint256 maxAssets_, uint256 deadline_, bytes signature_) external returns (uint256 assets_)

mint amount of shares_ with EIP-2612 Permit signature for underlying asset approval. IMPORTANT: This will revert if the underlying asset() does not support EIP-2612. Signature should approve a little bit more than expected assets amount (previewMint()) to avoid reverts. shares_ must at least be minMint() amount; reverts with fToken__DepositInsignificant() if not. Note there might be tiny inaccuracies between requested shares_ and actually received shares amount. Recommended to use deposit() over mint because it is more gas efficient and less likely to revert.

Parameters

Return Values

fTokenPermit2Deposits

implements fTokens support for deposit / mint via Permit2 signature.

depositWithSignature

function depositWithSignature(uint256 assets_, address receiver_, uint256 minAmountOut_, struct IAllowanceTransfer.PermitSingle permit_, bytes signature_) external returns (uint256 shares_)

deposit assets_ amount with Permit2 signature for underlying asset approval. reverts with fToken__MinAmountOut() if minAmountOut_ of shares is not reached. assets_ must at least be minDeposit() amount; reverts otherwise.

Parameters

Return Values

mintWithSignature

function mintWithSignature(uint256 shares_, address receiver_, uint256 maxAssets_, struct IAllowanceTransfer.PermitSingle permit_, bytes signature_) external returns (uint256 assets_)

mint amount of shares_ with Permit2 signature for underlying asset approval. Signature should approve a little bit more than expected assets amount (previewMint()) to avoid reverts. shares_ must at least be minMint() amount; reverts otherwise. Note there might be tiny inaccuracies between requested shares_ and actually received shares amount. Recommended to use deposit() over mint because it is more gas efficient and less likely to revert.

Parameters

Return Values

fToken

fToken is a token that can be used to supply liquidity to the Fluid Liquidity pool and earn interest for doing so. The fToken is backed by the underlying balance and can be redeemed for the underlying token at any time. The interest is earned via Fluid Liquidity, e.g. because borrowers pay a borrow rate on it. In addition, fTokens may also have active rewards going on that count towards the earned yield for fToken holders.

The fToken implements the ERC20 and ERC4626 standard, which means it can be transferred, minted and burned. The fToken supports EIP-2612 permit approvals via signature. The fToken implements withdrawals via EIP-2612 permits and deposits with Permit2 or EIP-2612 (if underlying supports it) signatures. fTokens are not upgradeable. For view methods / accessing data, use the "LendingResolver" periphery contract.

constructor

constructor(contract IFluidLiquidity liquidity_, contract IFluidLendingFactory lendingFactory_, contract IERC20 asset_) public

Parameters

decimals

function decimals() public view virtual returns (uint8)

Returns the decimals places of the token.

liquidityCallback

function liquidityCallback(address token_, uint256 amount_, bytes data_) external virtual

transfers amount_ of token_ to liquidity. Only callable by liquidity contract.

this callback is used to optimize gas consumption (reducing necessary token transfers).