VToken

Overview

The VToken contract is a custom lending token contract based on the ERC4626 standard. It wraps around an ERC20 token and extends functionalities to enable lending/borrowing with interest accrual, fees, and risk management.

It is designed to be composable, modular, and DeFi protocol-compatible, including roles like accountManager, interest rateModel, and integrations through a central Registry.

Initialization

Signature:

function init(
    ERC20 _asset,
    string calldata _name,
    string calldata _symbol,
    IRegistry _registry,
    uint _originationFee,
    address _treasury,
    uint _reserveShares,
    uint _maxSupply
) external

Parameters:

Parameter	Type	Description
_asset	ERC20	Address of the underlying token being lent (e.g. USDC, DAI).
_name	string	Human-readable name for the VToken (e.g. "vUSDC").
_symbol	string	Token symbol for the VToken (e.g. "vUSDC").
_registry	IRegistry	Contract used for resolving other system components like rate models.
_originationFee	uint	Fee (in 18 decimals) charged when a user borrows.
_treasury	address	Address where fees are sent.
_reserveShares	uint	Shares minted to address(0) to control utilization curve.
_maxSupply	uint	Cap on the maximum shares that can be minted.

Signature:

function initDep(string calldata _rateModel) external

Parameters:

Parameter	Type	Description
_rateModel	string	Identifier for the interest rate model contract inside the Registry.

Deposit

Function Signature:

function deposit(uint256 assets, address receiver) public override returns (uint256 shares)

Parameters:

Parameter	Type	Description
assets	uint256	The amount of the underlying asset to deposit into the vault.
receiver	address	The address to receive the minted vault shares.

Returns:

Return	Type	Description
shares	uint256	Amount of vault shares minted to the receiver.

Description: Deposits a specified amount of asset into the vault, and mints corresponding shares to the receiver. This function updates the interest rate model and internal accounting through beforeDeposit().

Withdraw

Function Signature:

function withdraw(uint256 assets, address receiver, address owner) public override returns (uint256 shares)

Parameters:

Parameter	Type	Description
assets	uint256	Amount of the underlying asset to withdraw from the vault.
receiver	address	Address that will receive the withdrawn asset.
owner	address	Address whose shares will be burned. If msg.sender != owner, allowance must be given.

Returns:

Return	Type	Description
shares	uint256	Amount of shares burned to withdraw the requested assets.

Description: Burns enough shares from owner to withdraw assets to receiver. Internal accounting and interest model are updated through beforeWithdraw().

Lending and Borrowing

Signature:

function lendTo(address account, uint amt) external returns (bool isFirstBorrow)

Parameters:

Parameter	Type	Description
account	address	Address of the borrower.
amt	uint	Amount of tokens to lend.

Returns: isFirstBorrow - true if the user is borrowing for the first time (no borrow shares before).

Signature:

function collectFrom(address account, uint amt) external returns (bool)

Parameters:

Parameter	Type	Description
account	address	Address of the borrower.
amt	uint	Amount to collect from the borrower (in underlying asset).

Returns: true if borrower has no debt left after collection.

Signature:

function getBorrowBalance(address account) external view returns (uint)

Parameters:

Parameter	Type	Description
account	address	Borrower address.

Returns: Amount of underlying tokens the user owes.

View Functions

Signature:

function totalAssets() public view override returns (uint)

Returns: Total assets managed by the vault = underlying balance + borrows + accrued interest.

Signature:

function getBorrows() public view returns (uint)

Returns: Total amount borrowed including interest accrued since the last update.

Signature:

function getRateFactor() internal view returns (uint)

Returns: Rate factor calculated based on timestamp delta * interest rate per second.

Signature:

function convertAssetToBorrowShares(uint amt) internal view returns (uint)

Parameters:

Parameter	Type	Description
amt	uint	Amount in underlying token.

Returns: Equivalent amount in borrow shares.

Signature:

function convertBorrowSharesToAsset(uint debt) internal view returns (uint)

Parameters:

Parameter	Type	Description
debt	uint	Amount in borrow shares.

Returns: Equivalent amount in underlying tokens.

Lifecycle Hooks

function beforeDeposit(uint, uint) internal override

Purpose: Updates interest state before a deposit.

function beforeWithdraw(uint, uint) internal override

Purpose: Updates interest state before a withdrawal.

State Management

Signature:

function updateState() public

Description: Accrues interest since the last update and updates borrows and lastUpdated.

Admin Functions

Signature:

function updateOriginationFee(uint _originationFee) external

Parameters:

Parameter	Type	Description
_originationFee	uint	New origination fee (scaled to 18 decimals).

Signature:

function updateMaxSupply(uint _maxSupply) external

Parameters:

Parameter	Type	Description
_maxSupply	uint	New maximum total share supply.