Comptroller

Introduction

The Comptroller is the risk management module of the JustLend DAO protocol. It determines how much collateral should users keep to avoid liquidation.

The Comptroller is implemented as an upgradable contract. The entrance is Unitroller; the implementation is Comptroller.

Solidity API

Markets

enterMarkets()

Calling this method enters a list of markets to supply or borrow.

function enterMarkets(address[] memory cTokens) public returns (uint[] memory)

Parameter description:

Parameter	Type	Description
cTokens	address[]	Address list of the markets to enter

Returns: For each market, returns 0 for success, otherwise an error code.

const result = comptroller.enterMarket(addresses).send({
  feeLimit:10_000_000_000,
  callValue:0,
  shouldPollResponse:true
});

---

exitMarket()

Calling this method exits a currently entered market.

function exitMarket(address cTokenAddress) external returns (uint)

Parameter description:

Parameter	Type	Description
cTokenAddress	address	Market address to quit

Returns: 0 on success, otherwise an error code.

const result = comptroller.exitMarket(address).send({
  feeLimit:10_000_000_000,
  callValue:0,
  shouldPollResponse:true
});

---

getAssetsIn()

Calling this method returns a list of already entered markets.

function getAssetsIn(address account) external view returns (CToken[] memory)

Parameter description:

Parameter	Type	Description
account	address	The markets this account enters will be returned

Returns: Markets have been entered by the specified address.

const result = comptroller.getAssetsIn(account).call();

---

markets()

Calling this method returns the status of a market(isListed, collateralFactorMantissa, comped)

function markets(address cTokenAddress) view returns (bool, uint, bool)

Parameter description:

Parameter	Type	Description
cTokenAddress	address	Market address

Return Values：

Returns	Type	Description
isListed	bool	Whether recognized by comptroller
collateralFactorMantissa	uint	The value can be borrowed(scaled by 1e18)
comped	bool	Whether suppliers & borrowers can get jst dividends

const {0: isListed, 1: collateralFactorMantissa, 2: isComped} = comptroller.markets(address).call();

Collateral & Liquidation

getAccountLiquidity()

Calling this method returns the liquidity and shortfall of a user.

function getAccountLiquidity(address account) public view returns (uint, uint, uint)

Parameter description:

Parameter	Type	Description
account	address	Address to be queried

Return Values：

Returns	Type	Description
error	uint	0 for success, otherwise an error code
liquidity	uint	current liquidity
shortfall	uint	The shortfall value of the account's collateral requirement

const {0: error, 1: liquidity, 2: shortfall} = comptroller.getAccountLiquidity(account).call();

---

closeFactorMantissa()

Calling this method gets the percentage of a liquidatable account should repay in a single liquidation. The range is 0%-100%. The calculation result of this method applies to a single asset.

function closeFactorMantissa() view returns (uint256)

Returns: The close factor, scaled by 1e18

const result = comptroller.closeFactorMantissa().call();

---

liquidationIncentiveMantissa()

Calling this method gets liquidators' incentives. The incentive is for underwater accounts. Part of this will be given to jToken reserves according to the seize share.

function liquidationIncentiveMantissa() view returns (uint256)

Returns: The liquidation incentive, scaled by 1e18

const result = comptroller.liquidationIncentiveMantissa().call();

Key Events

Event	Description
MarketEntered(address cToken, address account)	Emits when successfully entering a market
MarketExited(address cToken, address account)	Emits when successfully exit a market

Error Codes

Code	Name	Description
0	NO_ERROR	Success
1	UNAUTHORIZED	The sender is not authorized to perform this action.
2	COMPTROLLER_MISMATCH	Liquidation cannot be performed in markets with different comptrollers.
3	INSUFFICIENT_SHORTFALL	The account does not have sufficient shortfall to perform this action.
4	INSUFFICIENT_LIQUIDITY	The account does not have sufficient liquidity to perform this action.
5	INVALID_CLOSE_FACTOR	The close factor is not valid.
6	INVALID_COLLATERAL_FACTOR	The collateral factor is not valid.
7	INVALID_LIQUIDATION_INCENTIVE	The liquidation incentive is invalid.
8	MARKET_NOT_ENTERED	The market has not been entered by the account.
9	MARKET_NOT_LISTED	The market is not currently listed by the comptroller.
10	MARKET_ALREADY_LISTED	An admin tried to list the same market more than once.
11	MATH_ERROR	A math calculation error occurred.
12	NONZERO_BORROW_BALANCE	The action cannot be performed since the account carries a borrow balance.
13	PRICE_ERROR	The comptroller could not obtain a required price of an asset.
14	REJECTION	The comptroller rejects the action requested by the market.
15	SNAPSHOT_ERROR	The comptroller could not get the account borrows and exchange rate from the market.
16	TOO_MANY_ASSETS	Attempted to enter more markets than are currently supported.
17	TOO_MUCH_REPAY	Attempted to repay more than is allowed by the protocol.

Failure Info

Code	Value
0	ACCEPT_ADMIN_PENDING_ADMIN_CHECK
1	ACCEPT_PENDING_IMPLEMENTATION_ADDRESS_CHECK
2	EXIT_MARKET_BALANCE_OWED
3	EXIT_MARKET_REJECTION
4	SET_CLOSE_FACTOR_OWNER_CHECK
5	SET_CLOSE_FACTOR_VALIDATION
6	SET_COLLATERAL_FACTOR_OWNER_CHECK
7	SET_COLLATERAL_FACTOR_NO_EXISTS
8	SET_COLLATERAL_FACTOR_VALIDATION
9	SET_COLLATERAL_FACTOR_WITHOUT_PRICE
10	SET_IMPLEMENTATION_OWNER_CHECK
11	SET_LIQUIDATION_INCENTIVE_OWNER_CHECK
12	SET_LIQUIDATION_INCENTIVE_VALIDATION
13	SET_MAX_ASSETS_OWNER_CHECK
14	SET_PENDING_ADMIN_OWNER_CHECK
15	SET_PENDING_IMPLEMENTATION_OWNER_CHECK
16	SET_PRICE_ORACLE_OWNER_CHECK
17	SUPPORT_MARKET_EXISTS
18	SUPPORT_MARKET_OWNER_CHECK