BalancerQueries

0x3C612e132624f4Bd500eE1495F54565F0bcc9b59 | ABI JSON

This contract provides quotes on swaps, joins and exits, simulating these operations and returning the exact result they would have if called on the Vault given the current state.

WARNING

Be careful not to use these functions to calculate limits, maxAmountsIn or minAmountsOut from within a smart contract transaction.

Doing so will leave you vulnerable to sandwich attacks.

TIP

All of the functions are defined as mutable functions, instead of view, even though that is a common use case.

For example in ethers.js, the command would look something like:

const quote = await queryContract.callStatic.queryBatchSwap(0, [swap0, swap1], assets, funds)

Functions

querySwap

function querySwap(IVault.SingleSwap memory singleSwap, IVault.FundManagement memory funds)
    external
    returns (uint256);

queryBatchSwap

function queryBatchSwap(
    IVault.SwapKind kind,
    IVault.BatchSwapStep[] memory swaps,
    IAsset[] memory assets,
    IVault.FundManagement memory funds
) external returns (int256[] memory assetDeltas);

queryJoin

function queryJoin(bytes32 poolId, address sender, address recipient, IVault.JoinPoolRequest memory request)
    external
    returns (uint256 bptOut, uint256[] memory amountsIn);

queryExit

function queryExit(bytes32 poolId, address sender, address recipient, IVault.ExitPoolRequest memory request)
    external
    returns (uint256 bptIn, uint256[] memory amountsOut);

Structs

These structs do not belong to the Query contract, but are used as parameters in the functions above and provided for convenience below:

enum SwapKind { GIVEN_IN, GIVEN_OUT }

struct SingleSwap {
    bytes32 poolId;
    SwapKind kind;
    IAsset assetIn;
    IAsset assetOut;
    uint256 amount;
    bytes userData; // 0x for most swaps
}

struct FundManagement {
    address sender;
    bool fromInternalBalance;
    address payable recipient;
    bool toInternalBalance;
}

struct JoinPoolRequest {
    address[] assets,
    uint256[] maxAmountsIn,
    bytes userData,
    bool fromInternalBalance
}

struct ExitPoolRequest {
    address[] assets,
    uint256[] minAmountsOut,
    bytes userData,
    bool toInternalBalance
}