LP Tokens Contract

Overview

The Native LP Token contract is a yield-bearing vault that represents the shares and positions for all liquidity providers in Native.

The contract also helps distribute yield from the funding interest collected from private market makers, who utilise the liquidity to facilitate trading with Credit-Based swaps on the Native trading engine.

Note that the balance of the token directly represents the amount of underlying tokens in users' addresses, as well as the totalSupply number. To get shares, use shares and totalShares.

Inherits

ERC20, Ownable, ReentrancyGuardTransient, Pausable

State Variables

underlying

The underlying token that this LP token represents

IERC20Metadata public underlying;

creditVault

The address of the credit vault contract

address public creditVault;

_decimals

The number of decimals for this token, matching the underlying token's decimals

uint8 private _decimals;

earlyWithdrawFeeBips

Early withdrawal fee in basis points (1 bip = 0.01%)

Applied to prevent front-running by users who deposit right before yield distribution and immediately redeem after

uint256 public earlyWithdrawFeeBips;

totalUnderlying

Total amount of underlying assets deposited by LPs

uint256 public totalUnderlying;

totalShares

Total number of shares issued

uint256 public totalShares;

minRedeemInterval

Minimum time interval between deposit and redeem (in seconds)

uint256 public minRedeemInterval = 8 hours;

minDeposit

Minimum amount required for deposits

uint256 public minDeposit;

shares

Mapping of user addresses to their share balances

mapping(address => uint256) public shares;

lastDepositTimestamp

Mapping of user addresses to their last deposit timestamp

mapping(address => uint256) public lastDepositTimestamp;

Functions

constructor

constructor(
    string memory _name,
    string memory _symbol,
    address _underlying,
    address _creditVault
) ERC20(_name, _symbol);

deposit

Deposit underlying tokens to mint LP tokens

function deposit(
    uint256 amount
) external nonReentrant whenNotPaused returns (uint256 sharesToMint);

Parameters

Name	Type	Description
amount	uint256	Amount of underlying tokens to deposit

Returns

Name	Type	Description
sharesToMint	uint256	Amount of shares to be minted

redeem

Redeem LP tokens for underlying tokens

function redeem(
    uint256 sharesToBurn
) external nonReentrant whenNotPaused returns (uint256 underlyingAmount);

Parameters

Name	Type	Description
sharesToBurn	uint256	Amount of shares to burn

Returns

Name	Type	Description
underlyingAmount	uint256	Amount of underlying tokens received

distributeYield

Distributes yield to LP token holders

Can only be called by the credit vault

function distributeYield(
    uint256 yieldAmount
) external;

Parameters

Name	Type	Description
yieldAmount	uint256	Amount of yield to distribute

balanceOf

Gets the underlying token balance of an account

function balanceOf(
    address account
) public view override returns (uint256);

Parameters

Name	Type	Description
account	address	The address to check the balance for

Returns

Name	Type	Description
<none>	uint256	The amount of underlying tokens the account effectively owns

totalSupply

Gets the total supply of underlying tokens in the pool

function totalSupply() public view override returns (uint256);

Returns

Name	Type	Description
<none>	uint256	The total amount of underlying tokens managed by this contract

sharesOf

Gets the number of shares owned by an account

function sharesOf(
    address account
) public view returns (uint256);

Parameters

Name	Type	Description
account	address	The address to check shares for

Returns

Name	Type	Description
<none>	uint256	The number of shares owned by the account

getUnderlyingByShares

Calculates the underlying token amount for a given number of shares

function getUnderlyingByShares(
    uint256 sharesAmount
) public view returns (uint256);

Parameters

Name	Type	Description
sharesAmount	uint256	The number of shares to convert

Returns

Name	Type	Description
<none>	uint256	The corresponding amount of underlying tokens

getSharesByUnderlying

Calculates the number of shares for a given amount of underlying tokens

function getSharesByUnderlying(
    uint256 underlyingAmount
) public view returns (uint256);

Parameters

Name	Type	Description
underlyingAmount	uint256	The amount of underlying tokens to convert

Returns

Name	Type	Description
<none>	uint256	The corresponding number of shares

exchangeRate

Gets the current exchange rate between shares and underlying tokens

function exchangeRate() public view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	The exchange rate scaled by 1e18 (1:1 = 1e18)

decimals

Gets the number of decimals for this token

function decimals() public view override returns (uint8);

Returns

Name	Type	Description
<none>	uint8	The number of decimals, matching the underlying token

pause

Pauses all deposit and redeem operations

Can only be called by the owner

function pause() external onlyOwner;

unpause

Unpauses all deposit and redeem operations

Can only be called by the owner

function unpause() external onlyOwner;

setMinDeposit

Sets the minimum deposit amount

Can only be called by the owner

function setMinDeposit(
    uint256 _minDeposit
) external onlyOwner;

Parameters

Name	Type	Description
_minDeposit	uint256	New minimum deposit amount

setMinRedeemInterval

Sets the minimum time interval required between deposit and redeem

Can only be called by the owner

function setMinRedeemInterval(
    uint256 _interval
) external onlyOwner;

Parameters

Name	Type	Description
_interval	uint256	New minimum interval in seconds

setEarlyWithdrawFeeBips

Sets the early withdrawal fee in basis points (BIPs)

Can only be called by the owner

function setEarlyWithdrawFeeBips(
    uint256 _earlyWithdrawFeeBips
) external onlyOwner;

Parameters

Name	Type	Description
_earlyWithdrawFeeBips	uint256	New early withdrawal fee in BIPs

_mintShares

function _mintShares(address to, uint256 shareAmount) internal;

_burnShares

function _burnShares(address from, uint256 shareAmount) internal;

_transferShares

function _transferShares(address from, address to, uint256 _shares) internal;

_transfer

Override ERC20's _transfer to handle yield-bearing LP token transfers

Since this is a yield-bearing token, the actual transfer is done by transferring shares rather than token amounts directly. The shares represent the user's proportion of the total underlying assets including yield.

function _transfer(address from, address to, uint256 amount) internal override;

Parameters

Name	Type	Description
from	address	The address to transfer from
to	address	The address to transfer to
amount	uint256	The underlying token amount to transfer

Events

YieldDistributed

Event emitted when yield is distributed to LP holders

event YieldDistributed(uint256 yieldAmount);

MinRedeemIntervalUpdated

Event emitted when minimum redeem interval is updated

event MinRedeemIntervalUpdated(uint256 newInterval);

TransferShares

Event emitted when shares are transferred between addresses

event TransferShares(address indexed from, address indexed to, uint256 shares);

SharesMinted

Event emitted when new shares are minted

event SharesMinted(address indexed user, uint256 shares, uint256 underlyingAmount);

SharesBurned

Event emitted when shares are burned

event SharesBurned(address indexed user, uint256 shares, uint256 underlyingAmount);

MinDepositUpdated

Event emitted when minimum deposit amount is updated

event MinDepositUpdated(uint256 oldAmount, uint256 newAmount);

EarlyWithdrawFeeBipsUpdated

Event emitted when early withdraw fee is updated

event EarlyWithdrawFeeBipsUpdated(uint256 oldFeeBips, uint256 newFeeBips);