Balancer adapter

Since all interaction with Balancer goes through the vault, there is only a single Vault adapter.

Note that the Balancer adapter restricts the set of pools that can be interacted with. Each poolID has one of 3 statuses:

NOT_ALLOWED - the pool cannot be interacted with.
ALLOWED - both swaps and liquidity provision are supported;
SWAPS_ONLY - only swaps are supported;

The current pool status can be retrieved by calling IBalancerV2Adapter.poolStatus(poolId).

State-changing functions

`swap`

Performs a swap within a single pool through the Vault.

function swap(SingleSwap memory singleSwap, FundManagement memory, uint256 limit, uint256 deadline)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
singleSwap	A struct with swap parameters. See Balancer documentation (opens in a new tab) for details.
limit	The minimum amount of tokens to receive from the swap.
deadline	Deadline for the swap to successfully execute.

funds parameter is ignored, because the adapter uses a single default FundManagement struct for all operations (as it does not use Balancer's internal balances, and sender/recipient is always the Credit Account).

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {SingleSwap, FundManagement} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IBalancerV2Vault.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
 
SingleSwap memory singleSwap = SingleSwap({
    poolId: poolId,
    kind: kind,
    assetIn: IAsset(assetIn),
    assetOut: IAsset(assetOut),
    amount: amount,
    userData: ""
});
 
FundManagement memory funds;
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.swap, (singleSwap, funds, limit, deadline))
});
 
creditFacade.multicall(calls);

`swapDiff`

Swaps the difference between the current balance of the asset and the specified leftoverAmount.

function swapDiff(SingleSwapDiff memory singleSwapDiff, uint256 limitRateRAY, uint256 deadline)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
singleSwapDiff	A struct with swap parameters. Same as `SingleSwap`, but without `SwapKind` and with amount replaced by `leftoverAmount`
limitRateRAY	The minimum exchange rate at which assets will be swapped.
deadline	Deadline for the swap to successfully execute.

Usage:

import {IBalancerV2Adapter, SingleSwapDiff} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
 
SingleSwapDiff memory singleSwapDiff = SingleSwapDiff({
    poolId: poolId,
    assetIn: IAsset(assetIn),
    assetOut: IAsset(assetOut),
    leftoverAmount: leftoverAmount,
    userData: ""
});
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.swapDiff, (singleSwapDiff, limitRateRAY, deadline))
});
 
creditFacade.multicall(calls);

`batchSwap`

Executes Balancer's batchSwap with the passed parameters. Only the funds parameters is changed. See Balancer documentation (opens in a new tab) for details.

function batchSwap(
    SwapKind kind,
    BatchSwapStep[] memory swaps,
    IAsset[] memory assets,
    FundManagement memory,
    int256[] memory limits,
    uint256 deadline
) external returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
kind	Type of a swap (`GIVEN_IN` or `GIVEN_OUT`)
swaps	Array of per-step swap parameters. See Balancer documentation (opens in a new tab) for details.
assets	Array of assets that participate in the swap.
limits	Limits for tokens spent and received, corresponding to assets. Negative values denote tokens being received by the user, and positive values denote tokens being spent by the user
deadline	Deadline for the swap to successfully execute.

Usage:

import {IAsset} from "../../integrations/balancer/IAsset.sol";
import {
    IBalancerV2Vault,
    SwapKind,
    FundManagement,
    BatchSwapStep
} from "../../integrations/balancer/IBalancerV2Vault.sol";
import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
 
...
 
BatchSwapStep[] memory steps = new BatchSwapStep[](1);
 
steps[0] = BatchSwapStep({
    poolId: poolId,
    assetInIndex: 0,
    assetOutIndex: 1,
    amount: amount,
    userData: ""
});
 
IAsset[] memory assets = new IAsset[](2);
assets[0] = IAsset(tokenIn);
assets[1] = IAsset(tokenOut);
 
FundManagement memory funds;
 
int256[] memory limits = new int256[](2);
 
limits[0] = 0;
limits[1] = limit;
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.batchSwapStep, (kind, steps, assets, funds, limits, deadline))
});
 
creditFacade.multicall(calls);

`joinPool`

Deposits assets to receive pool BPT in return.

function joinPool(bytes32 poolId, address, address, JoinPoolRequest memory request)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
poolId	ID of the pool to deposit into.
request	Struct encoding data to perform a deposit. See Balancer documentation (opens in a new tab) for more details.

sender and recipient are ignored, as they are automatically set to the Credit Account.

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {JoinPoolRequest} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IBalancerV2Vault.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
address[] memory assets = new address[](2);
 
assets[0] = asset0;
assets[1] = asset1;
 
uint256[] memory maxAmountsIn = new uint256[](2);
 
maxAmountsIn[0] = amount0;
maxAmountsIn[1] = amount1;
 
bytes memory userData = abi.encode(1, maxAmountsIn, minBPT);
 
JoinPoolRequest memory request = JoinPoolRequest({
    assets: assets,
    maxAmountsIn: maxAmountsIn,
    userData: userData,
    fromInternalBalance: false
});
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.joinPool, (poolId, address(0), address(0), request))
});
 
creditFacade.multicall(calls);

`joinPoolSingleAsset`

Deposits a specified amount of a single asset into the pool for BPT.

function joinPoolSingleAsset(bytes32 poolId, IAsset assetIn, uint256 amountIn, uint256 minAmountOut)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
poolId	ID of the pool to deposit into.
assetIn	Asset to deposit into the pool.
amountIn	Amount of asset to deposit.
minAmountOut	Minimal amount of BPT received

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.joinPoolSingleAsset, (poolId, IAsset(assetIn), amountIn, minAmountOut))
});
 
creditFacade.multicall(calls);

`joinPoolSingleAssetDiff`

Deposits the difference between the current asset balance and leftoverAmount into the pool to receive BPT.

function joinPoolSingleAssetDiff(bytes32 poolId, IAsset assetIn, uint256 leftoverAmount, uint256 minRateRAY)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
poolId	ID of the pool to deposit into.
assetIn	Asset to deposit into the pool.
leftoverAmount	Amount of asset to keep on the account.
minRateRAY	Minimal resulting exchange rate of asset to BPT.

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.joinPoolSingleAssetDiff, (poolId, IAsset(assetIn), leftoverAMount, minRateRAY))
});
 
creditFacade.multicall(calls);

`exitPool`

Burns BPT to withdraw funds from a pool.

function exitPool(bytes32 poolId, address, address payable, ExitPoolRequest memory request)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
poolId	ID of the pool to withdraw from.
request	Struct encoding data to perform a withdrawal. See Balancer documentation (opens in a new tab) for more details.

sender and recipient are ignored, as they are automatically set to the Credit Account.

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {ExitPoolRequest} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IBalancerV2Vault.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
address[] memory assets = new address[](2);
 
assets[0] = asset0;
assets[1] = asset1;
 
uint256[] memory minAmountsOut = new uint256[](2);
 
minAmountsOut[0] = minAmount0;
minAmountsOut[1] = minAmount1;
 
bytes memory userData = abi.encode(1, bptIn);
 
ExitPoolRequest memory request = ExitPoolRequest({
    assets: assets,
    minAmountsOut: minAmountsOut,
    userData: userData,
    toInternalBalance: false
});
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.exitPool, (poolId, address(0), address(0), request))
});
 
creditFacade.multicall(calls);

`exitPoolSingleAsset`

Burns BPT to receive a single asset from the pool.

function exitPoolSingleAsset(bytes32 poolId, IAsset assetOut, uint256 amountIn, uint256 minAmountOut)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
poolId	ID of the pool to withdraw from.
assetOut	Asset to withdraw from the pool.
amountIn	Amount of BPT to burn.
minAmountOut	Minimal amount of asset received.

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.exitPoolSingleAsset, (poolId, IAsset(assetOut), amountIn, minAmountOut))
});
 
creditFacade.multicall(calls);

`exitPoolSingleAssetDiff`

Burns the difference between the current balance of BPT and leftoverAmount to receive a single asset from the pool.

function exitPoolSingleAssetDiff(bytes32 poolId, IAsset assetOut, uint256 leftoverAmount, uint256 minAmountOut)
    external
    returns (uint256 tokensToEnable, uint256 tokensToDisable);

Parameter	Description
poolId	ID of the pool to withdraw from.
assetOut	Asset to withdraw from the pool.
leftoverAmount	Amount of BPT to keep on the account.
minRateRAY	Minimal exchange rate between BPT and withdrawn asset.

Usage:

import {IBalancerV2Adapter} from "@gearbox-protocol/integrations-v3/contracts/interfaces/balancer/IBalancerV2Adapter.sol";
import {IAsset} from "@gearbox-protocol/integrations-v3/contracts/integrations/balancer/IAsset.sol";
 
...
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = MultiCall({
    target: balancerVaultAdapter,
    callData: abi.encodeCall(IBalancerV2Adapter.exitPoolSingleAssetDiff, (poolId, IAsset(assetOut), leftoverAmount, minRateRAY))
});
 
creditFacade.multicall(calls);

Balancer Multicaller library

The BalancerV2 Vault adapter has a corresponding library that simplifies the MultiCall building API.

Usage example:

import {BalancerV2_Multicaller, BalancerV2_Calls} from "@gearbox-protocol/integrations-v3/test/multicall/balancer/BalancerV2_Calls.sol";
...
 
using BalancerV2_Calls for BalancerV2_Multicaller;
...
 
MultiCall[] memory calls = new MultiCall[](1);
calls[0] = BalancerV2_Multicaller(balancerVaultAdapter).joinPoolSingleAsset(poolId, IAsset(assetIn), amountIn, minAmountOut);
 
creditFacade.multicall(calls);

Last updated on November 16, 2023

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