StableDebtToken

https://github.com/Into-the-Fathom/fathom-lending-platform-smart-contracts/blob/master/contracts/protocol/tokenization/StableDebtToken.sol

The StableDebtToken is a specialized token in the Fathom protocol used to track borrowing positions at a stable interest rate. This token does not inherit from IERC20 to save on code size and avoids standard ERC20 functionalities such as transfers and approvals, given its non-transferable nature.

Events

• Initialized: Emitted when the token is initialized.

  • underlyingAsset: Address of the underlying asset.

  • pool: Address of the associated pool.

  • incentivesController: Address of the incentives controller.

  • debtTokenDecimals: Decimals of the debt token.

  • debtTokenName: Name of the debt token.

  • debtTokenSymbol: Symbol of the debt token.

  • params: Encoded parameters for additional initialization.

• Mint: Emitted when new stable debt is minted.

  • user: Address of the user who triggered the minting.

  • onBehalfOf: Address receiving the stable debt tokens.

  • amount: Amount minted (user-entered amount + balance increase from interest).

  • currentBalance: Balance of the user based on the previous balance and balance increase from interest.

  • balanceIncrease: Increase in balance since the last action of the user onBehalfOf.

  • newRate: Rate of the debt after the minting.

  • avgStableRate: Next average stable rate after the minting.

  • newTotalSupply: Next total supply of the stable debt token after the action.

• Burn: Emitted when stable debt is burned.

  • from: Address from which the debt will be burned.

  • amount: Amount being burned (user-entered amount - balance increase from interest).

  • currentBalance: Balance of the user based on the previous balance and balance increase from interest.

  • balanceIncrease: Increase in balance since the last action of from.

  • avgStableRate: Next average stable rate after the burning.

  • newTotalSupply: Next total supply of the stable debt token after the action.

Functions

initialize

Initializes the debt token.

• Parameters:

  • pool: The pool contract that is initializing this contract.

  • underlyingAsset: The address of the underlying asset of this debt token.

  • incentivesController: The smart contract managing potential incentives distribution.

  • debtTokenDecimals: The decimals of the debt token, same as the underlying asset's.

  • debtTokenName: The name of the token.

  • debtTokenSymbol: The symbol of the token.

  • params: Encoded parameters for additional initialization.

getAverageStableRate

Returns the average rate of all the stable rate loans.

• Returns:

  • The average stable rate.

getUserLastUpdated

Returns the timestamp of the last update of the user.

• Parameters:

  • user: The address of the user.

• Returns:

  • The timestamp.

getUserStableRate

Returns the stable rate of the user's debt.

• Parameters:

  • user: The address of the user.

• Returns:

  • The stable rate of the user.

balanceOf

Returns the balance of a user.

• Parameters:

  • account: The address of the user.

• Returns:

  • The balance of the user.

mint

Mints debt tokens to the onBehalfOf address.

• Parameters:

  • user: The address receiving the borrowed underlying.

  • onBehalfOf: The address receiving the debt tokens.

  • amount: The amount of debt tokens to mint.

  • rate: The rate of the debt being minted.

• Returns:

  • bool: True if it is the first borrow, false otherwise.

  • uint256: The total stable debt.

  • uint256: The average stable borrow rate.

burn

Burns debt of user.

• Parameters:

  • from: The address from which the debt will be burned.

  • amount: The amount of debt tokens getting burned.

• Returns:

  • uint256: The total stable debt.

  • uint256: The average stable borrow rate.

getSupplyData

Returns the principal, the total supply, the average stable rate, and the timestamp for the last update.

• Returns:

  • uint256: The principal.

  • uint256: The total supply.

  • uint256: The average stable rate.

  • uint40: The timestamp of the last update.

getTotalSupplyAndAvgRate

Returns the total supply and the average stable rate.

• Returns:

  • uint256: The total supply.

  • uint256: The average rate.

totalSupply

Returns the total supply of the stable debt tokens.

• Returns:

  • The total supply.

getTotalSupplyLastUpdated

Returns the timestamp of the last update of the total supply.

• Returns:

  • The timestamp.

principalBalanceOf

Returns the principal debt balance of the user.

• Parameters:

  • user: The address of the user.

• Returns:

  • The debt balance of the user since the last burn/mint action.

UNDERLYING_ASSET_ADDRESS

Returns the address of the underlying asset of this stable debt token.

• Returns:

  • The address of the underlying asset.

Non-Implemented ERC20 Functions

The following ERC20 functions are not implemented because StableDebtToken is non-transferable:

• transfer

• allowance

• approve

• transferFrom

• increaseAllowance

• decreaseAllowance