Hooks
Hooks have access to different data shared from the Vault. These allow a developer to build powerful execution logic when additionally utilizing the shared data.
onRegister
function onRegister(
address factory,
address pool,
TokenConfig[] memory tokenConfig,
LiquidityManagement calldata liquidityManagement
) external returns (bool);
Hook to be executed when pool is registered. If it returns false, the registration is reverted. Vault address can be accessed with msg.sender.
Parameters:
| Name | Type | Description |
|---|---|---|
| factory | address | Address of the pool factory |
| pool | address | Address of the pool |
| tokenConfig | TokenConfig[] memory | An array of descriptors for the tokens the pool will manage |
| liquidityManagement | LiquidityManagement calldata | Liquidity management flags with implemented methods |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the hook allowed the registration, false otherwise |
getHookFlags
function getHookFlags() external returns (HookFlags memory hookFlags);
Returns flags informing which hooks are implemented in the contract.
Returns:
| Name | Type | Description |
|---|---|---|
| hookFlags | HookFlags memory | Flags indicating which hooks the contract supports |
onBeforeInitialize
function onBeforeInitialize(uint256[] memory exactAmountsIn, bytes memory userData) external returns (bool);
Optional hook to be executed before pool initialization. Note that unlike the swap and liquidity hooks, the initialize hooks are non-reentrant.
Parameters:
| Name | Type | Description |
|---|---|---|
| exactAmountsIn | uint256[] memory | Exact amounts of input tokens |
| userData | bytes memory | Optional, arbitrary data with the encoded request |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with initialization |
onAfterInitialize
function onAfterInitialize(
uint256[] memory exactAmountsIn,
uint256 bptAmountOut,
bytes memory userData
) external returns (bool);
Optional hook to be executed after pool initialization. Note that unlike the swap and liquidity hooks, the initialize hooks are non-reentrant.
Parameters:
| Name | Type | Description |
|---|---|---|
| exactAmountsIn | uint256[] memory | Exact amounts of input tokens |
| bptAmountOut | uint256 | Amount of pool tokens minted during initialization |
| userData | bytes memory | Optional, arbitrary data with the encoded request |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with initialization |
onBeforeAddLiquidity
function onBeforeAddLiquidity(
address router,
address pool,
AddLiquidityKind kind,
uint256[] memory maxAmountsInScaled18,
uint256 minBptAmountOut,
uint256[] memory balancesScaled18,
bytes memory userData
) external returns (bool success);
Optional hook to be executed before adding liquidity.
Parameters:
| Name | Type | Description |
|---|---|---|
| router | address | The address (usually a router contract) that initiated a swap operation on the Vault |
| pool | address | Pool address, used to fetch pool information from the Vault (pool config, tokens, etc.) |
| kind | AddLiquidityKind | The type of add liquidity operation (e.g., proportional, custom) |
| maxAmountsInScaled18 | uint256[] memory | Maximum amounts of input tokens |
| minBptAmountOut | uint256 | Minimum amount of output pool tokens |
| balancesScaled18 | uint256[] memory | Current pool balances in token registration order |
| userData | bytes memory | Optional, arbitrary data with the encoded request |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
onAfterAddLiquidity
function onAfterAddLiquidity(
address router,
address pool,
uint256[] memory amountsInScaled18,
uint256[] memory amountsInRaw,
uint256 bptAmountOut,
uint256[] memory balancesScaled18,
bytes memory userData
) external returns (bool success, uint256[] memory hookAdjustedAmountsInRaw);
Optional hook to be executed after adding liquidity.
Parameters:
| Name | Type | Description |
|---|---|---|
| router | address | The address (usually a router contract) that initiated a swap operation on the Vault |
| pool | address | Pool address, used to fetch pool information from the Vault (pool config, tokens, etc.) |
| amountsInScaled18 | uint256[] memory | Actual amounts of tokens added, sorted in token registration order |
| amountsInRaw | uint256[] memory | Actual amounts of tokens added, sorted in token registration order |
| bptAmountOut | uint256 | Amount of pool tokens minted |
| balancesScaled18 | uint256[] memory | Current pool balances in token registration order |
| userData | bytes memory | Additional (optional) data provided by the user |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
| hookAdjustedAmountsInRaw | uint256[] memory | New amountsInRaw, potentially modified by the hook |
onBeforeRemoveLiquidity
function onBeforeRemoveLiquidity(
address router,
address pool,
RemoveLiquidityKind kind,
uint256 maxBptAmountIn,
uint256[] memory minAmountsOutScaled18,
uint256[] memory balancesScaled18,
bytes memory userData
) external returns (bool success);
Optional hook to be executed before removing liquidity.
Parameters:
| Name | Type | Description |
|---|---|---|
| router | address | The address (usually a router contract) that initiated a swap operation on the Vault |
| pool | address | Pool address, used to fetch pool information from the Vault (pool config, tokens, etc.) |
| kind | RemoveLiquidityKind | The type of remove liquidity operation (e.g., proportional, custom) |
| maxBptAmountIn | uint256 | Maximum amount of input pool tokens |
| minAmountsOutScaled18 | uint256[] memory | Minimum output amounts in token registration order |
| balancesScaled18 | uint256[] memory | Current pool balances in token registration order |
| userData | bytes memory | Optional, arbitrary data with the encoded request |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
onAfterRemoveLiquidity
function onAfterRemoveLiquidity(
address router,
address pool,
RemoveLiquidityKind kind,
uint256 bptAmountIn,
uint256[] memory amountsOutScaled18,
uint256[] memory amountsOutRaw,
uint256[] memory balancesScaled18,
bytes memory userData
) external returns (bool success, uint256[] memory hookAdjustedAmountsOutRaw);
Optional hook to be executed after removing liquidity.
Parameters:
| Name | Type | Description |
|---|---|---|
| router | address | The address (usually a router contract) that initiated a swap operation on the Vault |
| pool | address | Pool address, used to fetch pool information from the Vault (pool config, tokens, etc.) |
| kind | RemoveLiquidityKind | The type of remove liquidity operation (e.g., proportional, custom) |
| bptAmountIn | uint256 | Amount of pool tokens to burn |
| amountsOutScaled18 | uint256[] memory | Scaled amount of tokens to receive, in token registration order |
| amountsOutRaw | uint256[] memory | Actual amount of tokens to receive, in token registration order |
| balancesScaled18 | uint256[] memory | Current pool balances in token registration order |
| userData | bytes memory | Additional (optional) data provided by the user |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
| hookAdjustedAmountsOutRaw | uint256[] memory | New amountsOutRaw, potentially modified by the hook |
onBeforeSwap
function onBeforeSwap(PoolSwapParams calldata params, address pool) external returns (bool success);
Called before a swap to give the Pool an opportunity to perform actions.
Parameters:
| Name | Type | Description |
|---|---|---|
| params | PoolSwapParams | Swap parameters |
| pool | address | Pool address, used to get pool information from the vault |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
onAfterSwap
function onAfterSwap(
AfterSwapParams calldata params
) external returns (bool success, uint256 hookAdjustedAmountCalculatedRaw);
Called after a swap to give the Pool an opportunity to perform actions once the balances have been updated by the swap.
Parameters:
| Name | Type | Description |
|---|---|---|
| params | AfterSwapParams | Swap parameters |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
| hookAdjustedAmountCalculatedRaw | uint256 | New amount calculated, modified by the hook |
onComputeDynamicSwapFeePercentage
function onComputeDynamicSwapFeePercentage(
PoolSwapParams calldata params,
address pool,
uint256 staticSwapFeePercentage
) external view returns (bool success, uint256 dynamicSwapFeePercentage);
Called after onBeforeSwap and before the main swap operation, if the pool has dynamic fees.
Parameters:
| Name | Type | Description |
|---|---|---|
| params | PoolSwapParams | Swap parameters |
| pool | address | Address of the pool |
| staticSwapFeePercentage | uint256 | Value of the static swap fee, for reference |
Returns:
| Name | Type | Description |
|---|---|---|
| success | bool | True if the pool wishes to proceed with settlement |
| dynamicSwapFeePercentage | uint256 | Value of the swap fee |