mToken

Inherits: mTokenConfiguration, ReentrancyGuard

Title: Core mToken logic

Author: Merge Layers Inc.

Base ERC-20 compatible lending token logic

Functions

constructor

Sets initial borrow rate max mantissa

constructor() ;

transfer

Transfers amount tokens to the dst address

function transfer(address dst, uint256 amount) external override nonReentrant returns (bool);

Parameters

Name	Type	Description
`dst`	`address`	The address of the recipient
`amount`	`uint256`	The number of tokens to transfer

Returns

Name	Type	Description
`<none>`	`bool`	success Whether the transfer was successful or not

transferFrom

Transfers amount tokens from the src address to the dst address

function transferFrom(address src, address dst, uint256 amount) external override nonReentrant returns (bool);

Parameters

Name	Type	Description
`src`	`address`	The address from which tokens are transferred
`dst`	`address`	The address to which tokens are transferred
`amount`	`uint256`	The number of tokens to transfer

Returns

Name	Type	Description
`<none>`	`bool`	success Whether the transfer was successful or not

approve

Approves spender to spend amount tokens on behalf of the caller

function approve(address spender, uint256 amount) external override returns (bool);

Parameters

Name	Type	Description
`spender`	`address`	The address authorized to spend tokens
`amount`	`uint256`	The number of tokens to approve

Returns

Name	Type	Description
`<none>`	`bool`	success Whether the approval was successful or not

totalBorrowsCurrent

Returns the total amount of borrows, accounting for interest

function totalBorrowsCurrent() external override nonReentrant returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	totalBorrowsCurrentAmount The total amount of borrows

borrowBalanceCurrent

Returns the current borrow balance for account, accounting for interest

function borrowBalanceCurrent(address account) external override nonReentrant returns (uint256);

Parameters

Name	Type	Description
`account`	`address`	The address to query the borrow balance for

Returns

Name	Type	Description
`<none>`	`uint256`	borrowBalance Current borrow balance

seize

Transfers collateral tokens (this market) to the liquidator.

Will fail unless called by another mToken during the process of liquidation. Its absolutely critical to use msg.sender as the borrowed mToken and not a parameter.

function seize(address liquidator, address borrower, uint256 seizeTokens) external override nonReentrant;

Parameters

Name	Type	Description
`liquidator`	`address`	The account receiving seized collateral
`borrower`	`address`	The account having collateral seized
`seizeTokens`	`uint256`	The number of mTokens to seize

reduceReserves

Accrues interest and reduces reserves by transferring to admin

function reduceReserves(uint256 reduceAmount) external override nonReentrant;

Parameters

Name	Type	Description
`reduceAmount`	`uint256`	Amount of reduction to reserves

balanceOfUnderlying

Returns the underlying asset balance of the owner

function balanceOfUnderlying(address owner) external override returns (uint256);

Parameters

Name	Type	Description
`owner`	`address`	The address to query the balance of underlying assets for

Returns

Name	Type	Description
`<none>`	`uint256`	balance The balance of underlying assets owned by `owner`

allowance

Returns the current allowance the spender has from the owner

function allowance(address owner, address spender) external view override returns (uint256);

Parameters

Name	Type	Description
`owner`	`address`	The address of the token holder
`spender`	`address`	The address authorized to spend the tokens

Returns

Name	Type	Description
`<none>`	`uint256`	allowanceAmount The current remaining number of tokens `spender` can spend

balanceOf

Returns the value of tokens owned by account.

function balanceOf(address owner) external view override returns (uint256);

Parameters

Name	Type	Description
`owner`	`address`

Returns

Name	Type	Description
`<none>`	`uint256`	balance Token balance of account

getAccountSnapshot

Returns the snapshot of account details for the given account

function getAccountSnapshot(address account)
    external
    view
    override
    returns (uint256 tokenBalance, uint256 borrowBalance, uint256 exchangeRate);

Parameters

Name	Type	Description
`account`	`address`	The address to query the account snapshot for

Returns

Name	Type	Description
`tokenBalance`	`uint256`	Token balance
`borrowBalance`	`uint256`	Borrow balance
`exchangeRate`	`uint256`	Exchange rate

borrowRatePerBlock

Returns the current borrow rate per block

function borrowRatePerBlock() external view override returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	borrowRate The current borrow rate per block, scaled by 1e18

supplyRatePerBlock

Returns the current supply rate per block

function supplyRatePerBlock() external view override returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	supplyRate The current supply rate per block, scaled by 1e18

borrowBalanceStored

Returns the stored borrow balance for account, without accruing interest

function borrowBalanceStored(address account) external view override returns (uint256);

Parameters

Name	Type	Description
`account`	`address`	The address to query the stored borrow balance for

Returns

Name	Type	Description
`<none>`	`uint256`	storedBalance The stored borrow balance

getCash

Returns the total amount of available cash in the contract

function getCash() external view override returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	cash The total amount of cash

exchangeRateStored

Returns the stored exchange rate, without accruing interest

function exchangeRateStored() external view override returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	exchangeRateStoredMantissa The stored exchange rate

exchangeRateCurrent

Returns the current exchange rate, with interest accrued

function exchangeRateCurrent() public override nonReentrant returns (uint256);

Returns

Name	Type	Description
`<none>`	`uint256`	exchangeRate The current exchange rate

_initializeMToken

Initialize the money market

function _initializeMToken(
    address operator_,
    address interestRateModel_,
    uint256 initialExchangeRateMantissa_,
    string memory name_,
    string memory symbol_,
    uint8 decimals_
) internal;

Parameters

Name	Type	Description
`operator_`	`address`	The address of the Operator
`interestRateModel_`	`address`	The address of the interest rate model
`initialExchangeRateMantissa_`	`uint256`	The initial exchange rate, scaled by 1e18
`name_`	`string`	EIP-20 name of this token
`symbol_`	`string`	EIP-20 symbol of this token
`decimals_`	`uint8`	EIP-20 decimal precision of this token

_mint

Sender supplies assets into the market and receives mTokens in exchange

Accrues interest whether or not the operation succeeds, unless reverted

function _mint(address user, address receiver, uint256 mintAmount, uint256 minAmountOut, bool doTransfer)
    internal
    nonReentrant;

Parameters

Name	Type	Description
`user`	`address`	The user address
`receiver`	`address`	The receiver address
`mintAmount`	`uint256`	The amount of the underlying asset to supply
`minAmountOut`	`uint256`	The minimum amount to be received
`doTransfer`	`bool`	If an actual transfer should be performed

_redeem

Sender redeems mTokens in exchange for the underlying asset

Accrues interest whether or not the operation succeeds, unless reverted

function _redeem(address user, uint256 redeemTokens, bool doTransfer)
    internal
    nonReentrant
    returns (uint256 underlyingAmount);

Parameters

Name	Type	Description
`user`	`address`	The user address
`redeemTokens`	`uint256`	The number of mTokens to redeem into underlying
`doTransfer`	`bool`	If an actual transfer should be performed

Returns

Name	Type	Description
`underlyingAmount`	`uint256`	Amount of underlying redeemed

_redeemUnderlying

Sender redeems mTokens in exchange for a specified amount of underlying asset

Accrues interest whether or not the operation succeeds, unless reverted

function _redeemUnderlying(address user, uint256 redeemAmount, bool doTransfer) internal nonReentrant;

Parameters

Name	Type	Description
`user`	`address`	The user address
`redeemAmount`	`uint256`	The amount of underlying to receive from redeeming mTokens
`doTransfer`	`bool`	If an actual transfer should be performed

_borrow

Sender borrows assets from the protocol to their own address

function _borrow(address user, uint256 borrowAmount, bool doTransfer) internal nonReentrant;

Parameters

Name	Type	Description
`user`	`address`	The user address
`borrowAmount`	`uint256`	The amount of the underlying asset to borrow
`doTransfer`	`bool`	If an actual transfer should be performed

_borrowWithReceiver

Sender borrows assets from the protocol to their own address

function _borrowWithReceiver(address user, address receiver, uint256 borrowAmount) internal nonReentrant;

Parameters

Name	Type	Description
`user`	`address`	The user address
`receiver`	`address`	The underlying receiver address
`borrowAmount`	`uint256`	The amount of the underlying asset to borrow

_repay

Sender repays their own borrow

function _repay(uint256 repayAmount, bool doTransfer) internal nonReentrant returns (uint256);

Parameters

Name	Type	Description
`repayAmount`	`uint256`	The amount to repay, or `type(uint256).max` for the full outstanding amount
`doTransfer`	`bool`	If an actual transfer should be performed

Returns

Name	Type	Description
`<none>`	`uint256`	actualRepay Amount actually repaid

_repayBehalf

Sender repays a borrow belonging to borrower

function _repayBehalf(address borrower, uint256 repayAmount, bool doTransfer)
    internal
    nonReentrant
    returns (uint256);

Parameters

Name	Type	Description
`borrower`	`address`	the account with the debt being payed off
`repayAmount`	`uint256`	The amount to repay, or `type(uint256).max` for the full outstanding amount
`doTransfer`	`bool`	If an actual transfer should be performed

Returns

Name	Type	Description
`<none>`	`uint256`	actualRepay Amount actually repaid

_liquidate

The sender liquidates the borrowers collateral. The collateral seized is transferred to the liquidator.

function _liquidate(
    address liquidator,
    address borrower,
    uint256 repayAmount,
    address mTokenCollateral,
    bool doTransfer
) internal nonReentrant;

Parameters

Name	Type	Description
`liquidator`	`address`	The liquidator address
`borrower`	`address`	The borrower of this mToken to be liquidated
`repayAmount`	`uint256`	The amount of the underlying borrowed asset to repay
`mTokenCollateral`	`address`	The market in which to seize collateral from the borrower
`doTransfer`	`bool`	If an actual transfer should be performed

_seize

Transfers collateral tokens (this market) to the liquidator.

Called only during an in-kind liquidation, or by liquidateBorrow during the liquidation of another mToken. It's absolutely critical to use msg.sender as the seizer mToken and not a parameter.

function _seize(address seizerToken, address liquidator, address borrower, uint256 seizeTokens) internal;

Parameters

Name	Type	Description
`seizerToken`	`address`	The contract seizing the collateral (i.e. borrowed mToken)
`liquidator`	`address`	The account receiving seized collateral
`borrower`	`address`	The account having collateral seized
`seizeTokens`	`uint256`	The number of mTokens to seize

_addReserves

Accrues interest and reduces reserves by transferring from msg.sender

function _addReserves(uint256 addAmount) internal nonReentrant;

Parameters

Name	Type	Description
`addAmount`	`uint256`	Amount of addition to reserves

__liquidate

The liquidator liquidates the borrowers collateral.

The collateral seized is transferred to the liquidator.

function __liquidate(
    address liquidator,
    address borrower,
    uint256 repayAmount,
    address mTokenCollateral,
    bool doTransfer
) internal;

Parameters

Name	Type	Description
`liquidator`	`address`	The address repaying the borrow and seizing collateral
`borrower`	`address`	The borrower of this mToken to be liquidated
`repayAmount`	`uint256`	The amount of the underlying borrowed asset to repay
`mTokenCollateral`	`address`	The market in which to seize collateral from the borrower
`doTransfer`	`bool`	If an actual transfer should be performed

_borrowBalanceStored

Return the borrow balance of account based on stored data

function _borrowBalanceStored(address account) internal view returns (uint256);

Parameters

Name	Type	Description
`account`	`address`	The address whose balance should be calculated

Returns

Name	Type	Description
`<none>`	`uint256`	borrowBalance Borrow balance with interest applied

__repay

Borrows are repaid by another user (possibly the borrower).

function __repay(address payer, address borrower, uint256 repayAmount, bool doTransfer) private returns (uint256);

Parameters

Name	Type	Description
`payer`	`address`	the account paying off the borrow
`borrower`	`address`	the account with the debt being payed off
`repayAmount`	`uint256`	the amount of underlying tokens being returned, or `type(uint256).max` for the full outstanding amount
`doTransfer`	`bool`	If an actual transfer should be performed

Returns

Name	Type	Description
`<none>`	`uint256`	Amount actually repaid

__borrow

Users borrow assets from the protocol to their own address

function __borrow(address payable borrower, address payable receiver, uint256 borrowAmount, bool doTransfer)
    private;

Parameters

Name	Type	Description
`borrower`	`address payable`	Borrower address
`receiver`	`address payable`	Receiver address
`borrowAmount`	`uint256`	The amount of the underlying asset to borrow
`doTransfer`	`bool`	If an actual transfer should be performed

__redeem

Executes redemption and performs transfers

function __redeem(address payable redeemer, uint256 redeemTokensIn, uint256 redeemAmountIn, bool doTransfer)
    private
    returns (uint256 redeemAmount);

Parameters

Name	Type	Description
`redeemer`	`address payable`	Address redeeming
`redeemTokensIn`	`uint256`	Number of tokens to redeem (if non-zero)
`redeemAmountIn`	`uint256`	Underlying amount to redeem (if non-zero)
`doTransfer`	`bool`	If an actual transfer should be performed

Returns

Name	Type	Description
`redeemAmount`	`uint256`	Underlying redeemed

__mint

User supplies assets into the market and receives mTokens in exchange

Assumes interest has already been accrued up to the current block

function __mint(address minter, address receiver, uint256 mintAmount, uint256 minAmountOut, bool doTransfer)
    private;

Parameters

Name	Type	Description
`minter`	`address`	The address of the account which is supplying the assets
`receiver`	`address`	The address of the account which is receiving the assets
`mintAmount`	`uint256`	The amount of the underlying asset to supply
`minAmountOut`	`uint256`	The min amount to be received
`doTransfer`	`bool`	If an actual transfer should be performed

_transferTokens

Transfer tokens tokens from src to dst by spender

Called by both transfer and transferFrom internally

function _transferTokens(address spender, address src, address dst, uint256 tokens) private;

Parameters

Name	Type	Description
`spender`	`address`	The address of the account performing the transfer
`src`	`address`	The address of the source account
`dst`	`address`	The address of the destination account
`tokens`	`uint256`	The number of tokens to transfer

__calculateSeizeTokens

Calculates seize token amount for liquidation

function __calculateSeizeTokens(address mTokenBorrowed, address mTokenCollateral, uint256 actualRepayAmount)
    private
    view
    returns (uint256 seizeTokens);

Parameters

Name	Type	Description
`mTokenBorrowed`	`address`	The market of the borrowed asset
`mTokenCollateral`	`address`	The market of the collateral asset
`actualRepayAmount`	`uint256`	Actual amount repaid

Returns

Name	Type	Description
`seizeTokens`	`uint256`	Amount of collateral tokens to seize

Malda