Pool

This contract is the main user-facing contract. Most user interactions with the Aave Protocol occur via the Pool contract. It exposes the liquidity management methods that can be invoked using either Solidity or Web3 libraries.

Pool.sol allows users to:

Pool is covered by a proxy contract and is owned by the PoolAddressesProvider of the specific market. All admin functions are callable by the PoolConfigurator contract defined in the PoolAddressesProvider.

The source code is available on GitHub.

function initialize(IPoolAddressesProvider provider) external virtual

Initializes the Pool.

Function is invoked by the proxy contract when the Pool contract is added to the PoolAddressesProvider of the market.

Caches the address of the PoolAddressesProvider in order to reduce gas consumption on subsequent operations.

function supply(    address asset,    uint256 amount,    address onBehalfOf,    uint16 referralCode) public virtual override

Supplies a certain amount of an asset into the protocol, minting the same amount of corresponding aTokens and transferring them to the onBehalfOf address. For example, if a user supplies 100 USDC and onBehalfOf address is the same as msg.sender, they will get 100 aUSDC in return.

The referralCode is emitted in Supply event and can be for third-party referral integrations. To activate the referral feature and obtain a unique referral code, integrators need to submit a proposal to Aave Governance.

function supplyWithPermit(    address asset,    uint256 amount,    address onBehalfOf,    uint16 referralCode,    uint256 deadline,    uint8 permitV,    bytes32 permitR,    bytes32 permitS) public virtual override

Supply with transfer approval of the asset to be supplied via permit function. This method removes the need for separate approval tx before supplying asset to the pool. See: https://eips.ethereum.org/EIPS/eip-2612.

function withdraw(address asset, uint256 amount, address to) public virtual override returns (uint256)

Withdraws an amount of underlying asset from the reserve, burning the equivalent aTokens owned. For example, if a user has 100 aUSDC and calls withdraw(), they will receive 100 USDC, burning the 100 aUSDC.

If user has any existing debt backed by the underlying token, then the maximum amount available to withdraw is the amount that will not leave user's health factor < 1 after withdrawal.

function borrow(    address asset,    uint256 amount,    uint256 interestRateMode,    uint16 referralCode,    address onBehalfOf) public virtual override

Allows users to borrow a specific amount of the reserve underlying asset, provided the borrower has already supplied enough collateral, or they were given enough allowance by a credit delegator on the corresponding debt token (VariableDebtToken). For example, if a user borrows 100 USDC passing their own address as onBehalfOf, they will receive 100 USDC into their wallet and 100 variable debt tokens.

function repay(    address asset,    uint256 amount,    uint256 interestRateMode,    address onBehalfOf) public virtual override returns (uint256)

Repays a borrowed amount on a specific reserve, burning the equivalent debt tokens owned. For example, if a user repays 100 USDC, the 100 variable debt tokens owned by the onBehalfOf address will be burned.

function repayWithPermit(    address asset,    uint256 amount,    uint256 interestRateMode,    address onBehalfOf,    uint256 deadline,    uint8 permitV,    bytes32 permitR,    bytes32 permitS) public virtual override returns (uint256)

Repay with transfer approval of the borrowed asset to be repaid, done via permit function. This method removes the need for separate approval tx before repaying asset to the pool. See: https://eips.ethereum.org/EIPS/eip-2612.

function repayWithATokens(address asset, uint256 amount, uint256 interestRateMode) public virtual override returns (uint256)

Allows a user to repay a borrowed amount on a specific reserve using the reserve aTokens, burning the equivalent debt tokens. For example, a user repays 100 USDC using 100 aUSDC, burning 100 variable debt tokens. Passing uint256.maxas the amount will clean up any residual aToken dust balance, if the user aToken balance is not enough to cover the whole debt.

function setUserUseReserveAsCollateral(address asset, bool useAsCollateral) public virtual override

Allows suppliers to enable/disable a specific supplied asset as collateral. Sets the asset of msg.sender to be used as collateral or not.

function liquidationCall(    address collateralAsset,    address debtAsset,    address user,    uint256 debtToCover,    bool receiveAToken) public virtual override

Function to liquidate a non-healthy position collateral-wise, with Health Factor below 1.

When the health factor of a position is below 1, the caller (liquidator) repays the debtToCover amount of debt of the user getting liquidated. This is part or all of the outstanding borrowed amount on behalf of the borrower. The caller then receives a proportional amount of the collateralAsset (discounted amount of collateral) plus a liquidation bonus to cover market risk.

Liquidators can decide if they want to receive an equivalent amount of collateral aTokens instead of the underlying asset. When the liquidation is completed successfully, the health factor of the position is increased, bringing the health factor above 1.

Liquidators can only close a certain amount of collateral defined by a close factor. Currently the close factor is 0.5. In other words, liquidators can only liquidate a maximum of 50% of the amount pending to be repaid in a position. The liquidation discount applies to this amount.

function flashLoan(    address receiverAddress,    address[] calldata assets,    uint256[] calldata amounts,    uint256[] calldata interestRateModes,    address onBehalfOf,    bytes calldata params,    uint16 referralCode) public virtual override

Allows users to access liquidity of the pool for a given list of assets within one transaction, as long as the amount taken plus a fee is returned. The receiver must approve the Pool contract for at least the amount borrowed + fee, otherwise the transaction will revert.

The flash loan fee is waived for approved FLASH_BORROWER.

function flashLoanSimple(    address receiverAddress,    address asset,    uint256 amount,    bytes calldata params,    uint16 referralCode) public virtual override

Allows users to access liquidity of the pool for a given asset within one transaction, as long as the amount taken plus a fee is returned. The receiver must approve the Pool contract for at least the amount borrowed + fee, otherwise the transaction will revert.

This function does not waive the fee for approved FLASH_BORROWER, nor does it allow for opening a debt position instead of repaying.

function mintToTreasury(address[] calldata assets) external virtual override

Mints the assets accrued through the reserve factor to the treasury in the form of aTokens for the given list of assets.

function finalizeTransfer(    address asset,    address from,    address to,    uint256 amount,    uint256 balanceFromBefore,    uint256 balanceToBefore) external virtual override

Validates and finalizes an aToken transfer. It is only callable by the overlying aToken of the asset.

function setUserEMode(uint8 categoryId) external virtual override

Allows a user to use the protocol in efficiency mode. The category id must be a valid id already defined by Pool or Risk Admins.

function mintUnbacked(    address asset,    uint256 amount,    address onBehalfOf,    uint16 referralCode) external virtual override onlyBridge

Allows contracts, with BRIDGE role permission, to mint an amount of unbacked aTokens to the onBehalfOf address. This method is part of the V3 Portals feature.

function backUnbacked(    address asset,    uint256 amount,    uint256 fee) external virtual override onlyBridge returns (uint256)

Allows contracts, with BRIDGE role permission, to back the current unbacked underlying aTokens with amount and pay fee. This method is part of the V3 Portals feature.

function initReserve(    address asset,    address aTokenAddress,    address stableDebtAddress,    address variableDebtAddress,    address interestRateStrategyAddress) external virtual override onlyPoolConfigurator

Initializes a reserve, activating it, assigning an aToken and debt tokens and an interest rate strategy.

function dropReserve(address asset) external virtual override onlyPoolConfigurator

Drop a reserve.

function setReserveInterestRateStrategyAddress(address asset, address rateStrategyAddress) external virtual override onlyPoolConfigurator

Updates the address of the interest rate strategy contract.

function setConfiguration(address asset, DataTypes.ReserveConfigurationMap calldata configuration) external virtual override onlyPoolConfigurator

Sets the configuration bitmap of the reserve as a whole.

The DataTypes.ReserveConfigurationMap struct is composed of the following fields:

function updateBridgeProtocolFee(uint256 protocolFee) external virtual override onlyPoolConfigurator

Updates the protocol fee on the bridging.

function updateFlashloanPremiums(uint128 flashLoanPremiumTotal, uint128 flashLoanPremiumToProtocol) external virtual override onlyPoolConfigurator

Updates flash loan premiums. A flash loan premium consists of two parts:

The total premium is calculated on the total borrowed amount. The premium to protocol is calculated on the total premium, being a percentage of flashLoanPremiumTotal.

function configureEModeCategory(uint8 id, DataTypes.EModeCategory memory category) external virtual override onlyPoolConfigurator

Configures a new category for the eMode. In eMode, the protocol allows very high borrowing power to borrow assets of the same category. The category 0 is reserved for volatile heterogeneous assets and it's always disabled.

Each eMode category has a custom ltv and liquidation threshold. Each eMode category may or may not have a custom oracle to override the individual assets price oracles.

The DataTypes.EModeCategory struct is composed of the following fields:

function resetIsolationModeTotalDebt(address asset) external virtual override onlyPoolConfigurator

Resets the isolation mode total debt of the given asset to zero. It requires the given asset to have a zero debt ceiling.

function rescueTokens(address token, address to, uint256 amount) external virtual override onlyPoolAdmin

Rescue and transfer tokens locked in this contract.

function getUserAccountData(address user) external view virtual override returns (    uint256 totalCollateralBase,    uint256 totalDebtBase,    uint256 availableBorrowsBase,    uint256 currentLiquidationThreshold,    uint256 ltv,    uint256 healthFactor)

Returns the user account data across all the reserves.

function getConfiguration(address asset) external view virtual override returns (DataTypes.ReserveConfigurationMap memory)

Returns the configuration of the reserve.

The DataTypes.ReserveConfigurationMap struct is composed of the following fields:

function getUserConfiguration(address user) external view virtual override returns (DataTypes.UserConfigurationMap memory)

Returns the configuration of the user across all the reserves.

The DataTypes.UserConfigurationMap struct is composed of the following fields:

function getReserveNormalizedIncome(address asset) external view virtual override returns (uint256)

Returns the ongoing normalized income for the reserve.

A value of 1e27 means there is no income. As time passes, the yield is accrued. A value of 2*1e27 means for each unit of asset, one unit of income has been accrued.

function getReserveNormalizedVariableDebt(address asset) external view virtual override returns (uint256)

Returns the normalized variable debt per unit of asset.

A value of 1e27 means there is no debt. As time passes, the debt is accrued. A value of 2*1e27 means that for each unit of debt, one unit worth of interest has been accumulated.

function getReservesList() external view virtual override returns (address[] memory)

Returns the list of the underlying assets of all the initialized reserves. It does not include dropped reserves.

function getReserveAddressById(uint16 id) external view returns (address)

Returns the address of the underlying asset of a reserve by the reserve id as stored in the DataTypes.ReserveData struct.

function getEModeCategoryData(uint8 id) external view virtual override returns (DataTypes.EModeCategory memory)

Returns the data of an eMode category.

Each eMode category has a custom LTV and liquidation threshold. Each eMode category may or may not have a custom oracle to override the individual assets' price oracles.

The DataTypes.EModeCategory struct is composed of the following fields:

function getReserveData(address asset) external view virtual override returns (DataTypes.ReserveData memory)

Returns the state and configuration of the reserve.

The DataTypes.ReserveData struct is composed of the following fields:

function getUserEMode(address user) external view virtual override returns (uint256)

Returns eMode the user is using. 0 is a non eMode category.

function FLASHLOAN_PREMIUM_TOTAL() public view virtual override returns (uint128)

Returns the percent of total flashloan premium paid by the borrower.

A part of this premium is added to reserve's liquidity index i.e. paid to the liquidity provider and the other part is paid to the protocol i.e. accrued to the treasury.

function BRIDGE_PROTOCOL_FEE() public view virtual override returns (uint256)

Returns the part of the bridge fees sent to protocol.

function FLASHLOAN_PREMIUM_TO_PROTOCOL() public view virtual override returns (uint128)

Returns the percent of flashloan premium that is accrued to the treasury.

function MAX_NUMBER_RESERVES() public view virtual override returns (uint16)

Returns the maximum number of reserves supported to be listed in this Pool.

function getRevision() internal pure virtual override returns (uint256)

Returns the revision number of the contract. Needs to be defined in the inherited class as a constant.

Returns 0x1.