(Legacy) Integrate X Swap Contract

XY Finance deploys smart contracts of Swapper (X Swap) on most mainstream chains and benefits all types of users in terms of secure cross-chain swaps.

yBridge has been updated to version v3, and this v2 documentation is currently only for reference purposes. If you need to integrate with our new contracts, please refer to Integrate YBridge Contract to get the latest information.

XSwapper

Code

To enable ease of access to the content of the smart contracts (its code, data, status, etc.) and ascertain how they work and how they are programmed on the network, here we give you (users and institutions alike) the APIs and custom-fit UIs to suit your needs and provide you with a sense of security. The link XSwapper.sol below offers a collection of our code and functions. The smart contract accounts, deployed to the network, will interact with you when you submit transactions that execute functions that are defined on the smart contracts per se. Just like a regular, typical contract, our smart contracts define rules and will automatically implement them via the code.

XSwapper

Events

System Setting Related Events

StartSwapIdSet

event StartSwapIdSet(uint256 _swapId);

This will be emitted when the starting swap ID is set.

FeeStructureSet

event FeeStructureSet(uint32 _toChainId, address _YPoolToken, uint256 _gas, uint256 _min, uint256 _max, uint256 _rate, uint256 _decimals);

This will be emitted when the fee structure of a certain liquidity pool token on a certain chain is set

YPoolVaultSet

event YPoolVaultSet(address _supportedToken, address _vault, bool _isSet);

This will be emitted when a Y Pool (liquidity pool) is set.

AggregatorAdaptorSet

event AggregatorAdaptorSet(address _aggregator, bool _isSet);

This will be emitted when an aggregator adaptor is set.

SwapValidatorXYChainSet

event SwapValidatorXYChainSet(address _swapValidatorXYChain);

This will be emitted when the validator address (on settlement chain) is set.

AcceptSwapRequestSet

event AcceptSwapRequestSet(bool _isSet);

This will be emitted when the acceptSwapRequest is set. If true, XSwapper accepts swap request.

X Swap Related Events

SwapRequested

event SwapRequested(uint256 _swapId, address indexed _aggregatorAdaptor, ToChainDescription _toChainDesc, IERC20 _fromToken, IERC20 indexed _YPoolToken, uint256 _YPoolTokenAmount, address _receiver, uint256 _xyFee, uint256 _gasFee);

This will be emitted whenever a cross-chain swap request is initiated.

CloseSwapCompleted

event CloseSwapCompleted(CloseSwapResult _swapResult, uint32 _fromChainId, uint256 _fromSwapId);

This will be emitted by the time all a cross-chain swap request is processed at the target chain so as to keep a record of the request.

SwappedForUser

event SwappedForUser(address indexed _aggregatorAdaptor, IERC20 indexed _fromToken, uint256 _fromTokenAmount, IERC20 _toToken, uint256 _toTokenAmountOut, address _receiver);

This will be emitted also by the time all a cross-chain swap request is processed at the target chain. However, this event records more information of the swap details than the CloseSwapCompleted event.

SwapCompleted

event SwapCompleted(CompleteSwapType _closeType, SwapRequest _swapRequest);

This will be emitted when a cross-chain swap request is completed at the source chain. That is, the asset is settled and claimed back to the liquidity pool.

State-Changing Functions

swap

function swap(
    address aggregatorAdaptor,
    IDexAggregatorAdaptor.SwapDescription memory swapDesc,
    bytes memory aggregatorData,
    ToChainDescription calldata toChainDesc
)

Initiate a cross-chain request and execute source chain side swap.

The aggregatorAdaptor is to adapt to the DEX aggregator involved in the aggregatorData.

The swapDesc contains the information of the source chain side swap.

struct SwapDescription {
    IERC20 fromToken;
    IERC20 toToken;
    address receiver;
    uint256 amount;
    uint256 minReturnAmount;
}

The aggregatorData is generated by server containing source chain part of best routing path.

The toChainDesc would be emitted in event to record target chain swap path and slippage. Note that the slippage would be seen as BP (1223 slippage equals to 12.23%).

struct ToChainDescription {
    uint32 toChainId;
    IERC20 toChainToken;
    uint256 expectedToChainTokenAmount;
    uint32 slippage;
}

swapWithReferrer

function swapWithReferrer(
    address aggregatorAdaptor,
    IDexAggregatorAdaptor.SwapDescription memory swapDesc,
    bytes memory aggregatorData,
    ToChainDescription calldata toChainDesc,
    address referrer
)

Initiate a cross-chain request and execute source chain side swap and leave a record of the referrer. Please contact us for more information about referral program.

singleChainSwap

function singleChainSwap(
    address aggregator,
    IDexAggregatorAdaptor.SwapDescription memory swapDesc,
    bytes memory aggregatorData
)

Execute a single-chain swap.

The aggregator is the DEX aggregator involved in the aggregatorData.

The swapDesc contains the information of the source chain side swap.

struct SwapDescription {
    IERC20 fromToken;
    IERC20 toToken;
    address receiver;
    uint256 amount;
    uint256 minReturnAmount;
}

The aggregatorData is generated by server containing source chain part of best routing path.

singleChainSwapWithReferrer

function singleChainSwapWithReferrer(
    address aggregator,
    IDexAggregatorAdaptor.SwapDescription memory swapDesc,
    bytes memory aggregatorData,
    address referrer
)

Execute a single-chain swap and leave a record of the referrer. Please contact us for more information about referral program.

View Functions

getSwapRequest

function getSwapRequest(uint256 _swapId) returns (SwapRequest)

Get a certain swap request information by swap ID

struct SwapRequest {
    uint32 toChainId;
    uint256 swapId;
    address receiver;
    address sender;
    uint256 YPoolTokenAmount;
    uint256 xyFee;
    uint256 gasFee;
    IERC20 YPoolToken;
    RequestStatus status;
}

enum RequestStatus { Open, Closed } 

getFeeStructure

function getFeeStructure(uint32 _chainId, address _token) returns (FeeStructure)

Get the fee setting of a certain liquidity pool token of a certain chain.

For example, if you are using Ethereum, you can get the fee setting of USDT pool of Ethereum by invoking getFeeStructure(1, "0xdAC17F958D2ee523a2206206994597C13D831ec7"); you can also get the fee setting of USDT pool of Polygon by invoking getFeeStructure(137, "0xdAC17F958D2ee523a2206206994597C13D831ec7"). This way you can figure out the fee setting when you try to bridge from Ethereum to Polygon via USDT pool.

struct FeeStructure {
    bool isSet;
    uint256 gas;
    uint256 min;
    uint256 max;
    uint256 rate;
    uint256 decimals;
}

// isSet: Has been set or not
// gas: gas amount
// min: minimum XY Fee amount
// max: maximum XY Fee amount
// rate: XY Fee rate
// decimals: decimals of `rate`

// Example:
// (True, 25000000, 40000000, 2000000000, 35, 5)
// Means the fee strucute is set with the following:
// The minimum XY Fee of the given chain and token is `40000000`
// The maximum XY Fee of the given chain and token is `2000000000`
// The part of gas amount (included in the XY Fee) is `25000000`
// The XY Fee rate is 35 / (10**5) == `0.035%`

getEverClosed

function getEverClosed(uint32 _chainId, uint256 _swapId) returns (bool)

Check whether a swap request is closed (processed) on target chain by the swap ID on the source chain and the source chain ID.

getTokenBalance

function getTokenBalance(IERC20 _token, address _account) returns (uint256)

Get balance of an account of a token.