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Solidity API

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RelayPool

ERC4626 vault that enables cross-chain asset bridging and yield generation

Receives bridged assets via Hyperlane, provides instant liquidity, and deposits idle funds into yield pools

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OriginSettings

Configuration for an authorized origin chain and bridge

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Parameters

struct OriginSettings {
  uint32 chainId;
  address bridge;
  address curator;
  uint256 maxDebt;
  uint256 outstandingDebt;
  address proxyBridge;
  uint32 bridgeFee;
  uint32 coolDown;
}

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OriginParam

Parameters for adding a new origin

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Parameters

struct OriginParam {
  address curator;
  uint32 chainId;
  address bridge;
  address proxyBridge;
  uint256 maxDebt;
  uint32 bridgeFee;
  uint32 coolDown;
}

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UnauthorizedCaller

error UnauthorizedCaller(address sender)

Error when caller is not authorized for the operation

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Parameters

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UnauthorizedSwap

error UnauthorizedSwap(address token)

Error when attempting to swap the pool’s underlying asset

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Parameters

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UnauthorizedOrigin

error UnauthorizedOrigin(uint32 chainId, address bridge)

Error when message is from an unauthorized origin

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Parameters

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MessageAlreadyProcessed

error MessageAlreadyProcessed(uint32 chainId, address bridge, uint256 nonce)

Error when attempting to process an already processed message

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Parameters

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TooMuchDebtFromOrigin

error TooMuchDebtFromOrigin(uint32 chainId, address bridge, uint256 maxDebt, uint256 nonce, address recipient, uint256 amount)

Error when origin would exceed its maximum allowed debt

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Parameters

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FailedTransfer

error FailedTransfer(address recipient, uint256 amount)

Error when native currency transfer fails

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Parameters

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InsufficientFunds

error InsufficientFunds(uint256 amount, uint256 balance)

Error when insufficient funds are available

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Parameters

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NotAWethPool

error NotAWethPool()

Error when native currency is sent to a non-WETH pool

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MessageTooRecent

error MessageTooRecent(uint32 chainId, address bridge, uint256 nonce, uint256 timestamp, uint32 coolDown)

Error when message timestamp is too recent based on cooldown period

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Parameters

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SharePriceTooLow

error SharePriceTooLow(uint256 actualPrice, uint256 minPrice)

Error when share price is below minimum acceptable threshold

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Parameters

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SharePriceTooHigh

error SharePriceTooHigh(uint256 actualPrice, uint256 maxPrice)

Error when share price is above maximum acceptable threshold

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Parameters

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HYPERLANE_MAILBOX

address HYPERLANE_MAILBOX

The address of the Hyperlane mailbox

Used to receive cross-chain messages

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WETH

address WETH

The address of the WETH contract (used for native pools)

Set to WETH address for native currency pools, otherwise can be address(0)

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FRACTIONAL_BPS_DENOMINATOR

uint256 FRACTIONAL_BPS_DENOMINATOR

Denominator for fractional basis points calculations (1 = 0.0000001 bps)

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outstandingDebt

uint256 outstandingDebt

Keeping track of the outstanding debt for ERC4626 computations

Represents funds that have been sent but not yet claimed from bridges

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authorizedOrigins

mapping(uint32 => mapping(address => struct RelayPool.OriginSettings)) authorizedOrigins

Mapping of origins to their settings

[chainId][bridgeAddress] => OriginSettings

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messages

mapping(uint32 => mapping(address => mapping(uint256 => bytes))) messages

Mapping of messages by origin

[chainId][bridgeAddress][nonce] => message data

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yieldPool

address yieldPool

The address of the yield pool where funds are deposited

Must be an ERC4626 vault for the same underlying asset

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tokenSwapAddress

address tokenSwapAddress

UniswapV3 wrapper contract for token swaps

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pendingBridgeFees

uint256 pendingBridgeFees

Keeping track of the total fees collected

Fees are held in the yield pool until they finish streaming

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totalAssetsToStream

uint256 totalAssetsToStream

All incoming assets are streamed (even though they are instantly deposited in the yield pool)

Total amount of assets currently being streamed

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lastAssetsCollectedAt

uint256 lastAssetsCollectedAt

Timestamp when assets were last collected for streaming

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endOfStream

uint256 endOfStream

Timestamp when current streaming period ends

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streamingPeriod

uint256 streamingPeriod

Duration over which collected assets are streamed

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LoanEmitted

event LoanEmitted(uint256 nonce, address recipient, contract ERC20 asset, uint256 amount, struct RelayPool.OriginSettings origin, uint256 fees)

Emitted when a loan is provided to a bridge recipient

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Parameters

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BridgeCompleted

event BridgeCompleted(uint32 chainId, address bridge, uint256 amount, uint256 fees)

Emitted when bridged funds are claimed and deposited

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Parameters

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OutstandingDebtChanged

event OutstandingDebtChanged(uint256 oldDebt, uint256 newDebt, struct RelayPool.OriginSettings origin, uint256 oldOriginDebt, uint256 newOriginDebt)

Emitted when outstanding debt changes

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Parameters

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AssetsDepositedIntoYieldPool

event AssetsDepositedIntoYieldPool(uint256 amount, address yieldPool)

Emitted when assets are deposited into the yield pool

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Parameters

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AssetsWithdrawnFromYieldPool

event AssetsWithdrawnFromYieldPool(uint256 amount, address yieldPool)

Emitted when assets are withdrawn from the yield pool

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Parameters

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TokenSwapChanged

event TokenSwapChanged(address prevAddress, address newAddress)

Emitted when the token swap address is changed

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Parameters

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YieldPoolChanged

event YieldPoolChanged(address oldPool, address newPool)

Emitted when the yield pool is changed

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Parameters

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StreamingPeriodChanged

event StreamingPeriodChanged(uint256 oldPeriod, uint256 newPeriod)

Emitted when the streaming period is changed

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Parameters

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OriginAdded

event OriginAdded(struct RelayPool.OriginParam origin)

Emitted when a new origin is added

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Parameters

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OriginDisabled

event OriginDisabled(uint32 chainId, address bridge, uint256 maxDebt, uint256 outstandingDebt, address proxyBridge)

Emitted when an origin is disabled

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Parameters

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constructor

constructor(address hyperlaneMailbox, contract ERC20 asset, string name, string symbol, address baseYieldPool, address weth, address curator) public

Initializes the RelayPool with core parameters

Warning: the owner should always be a timelock with significant delay

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Parameters

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updateStreamingPeriod

function updateStreamingPeriod(uint256 newPeriod) public

Updates the streaming period for fee accrual

Updates streamed assets before changing the period

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Parameters

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updateYieldPool

function updateYieldPool(address newPool, uint256 minSharePriceFromOldPool, uint256 maxSharePricePriceFromNewPool) public

Updates the yield pool, moving all assets from the old pool to the new one

Implements share price-based slippage protection to ensure fair value transfer

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Parameters

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addOrigin

function addOrigin(struct RelayPool.OriginParam origin) public

Adds a new authorized origin for bridging

Only callable by owner, typically a timelock contract

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Parameters

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disableOrigin

function disableOrigin(uint32 chainId, address bridge) public

Disables an origin by setting its max debt to zero

Only callable by the origin’s curator for emergency response

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Parameters

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increaseOutstandingDebt

function increaseOutstandingDebt(uint256 amount, struct RelayPool.OriginSettings origin) internal

Increases outstanding debt for an origin

Updates both origin-specific and total outstanding debt

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Parameters

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decreaseOutstandingDebt

function decreaseOutstandingDebt(uint256 amount, struct RelayPool.OriginSettings origin) internal

Decreases outstanding debt for an origin

Updates both origin-specific and total outstanding debt

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Parameters

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maxDeposit

function maxDeposit(address) public view returns (uint256 maxAssets)

Returns the maximum assets that can be deposited

Limited by the yield pool’s capacity

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Parameters

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Return Values

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maxWithdraw

function maxWithdraw(address owner) public view returns (uint256 maxAssets)

Returns the maximum assets that can be withdrawn by an owner

Limited to the owner’s share balance converted to assets

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Parameters

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Return Values

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maxMint

function maxMint(address receiver) public view returns (uint256 maxShares)

Returns the maximum shares that can be minted

Limited by the yield pool’s deposit capacity

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Parameters

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Return Values

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maxRedeem

function maxRedeem(address owner) public view returns (uint256 maxShares)

Returns the maximum shares that can be redeemed by an owner

Limited by the owner’s share balance and yield pool’s withdrawal capacity

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Parameters

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Return Values

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totalAssets

function totalAssets() public view returns (uint256)

Returns the total assets controlled by the pool

Includes yield pool balance, outstanding debt, minus pending fees and streaming assets

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Return Values

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depositAssetsInYieldPool

function depositAssetsInYieldPool(uint256 amount) internal

Deposits assets into the yield pool

Internal function that approves and deposits to yield pool

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Parameters

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withdrawAssetsFromYieldPool

function withdrawAssetsFromYieldPool(uint256 amount, address recipient) internal

Withdraws assets from the yield pool

Internal function that withdraws from yield pool to recipient

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Parameters

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handle

function handle(uint32 chainId, bytes32 bridgeAddress, bytes data) external payable

Handles incoming cross-chain messages from Hyperlane

Only callable by Hyperlane mailbox, provides instant liquidity to recipients

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Parameters

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remainsToStream

function remainsToStream() internal view returns (uint256)

Calculates remaining assets to be streamed

Returns zero if streaming period has ended

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Return Values

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updateStreamedAssets

function updateStreamedAssets() public returns (uint256)

Updates the streamed assets calculation

Resets the streaming calculation to current timestamp

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Return Values

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addToStreamingAssets

function addToStreamingAssets(uint256 amount) internal returns (uint256)

Adds assets to be accounted for in a streaming fashion

Adjusts streaming end time based on weighted average

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Parameters

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Return Values

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claim

function claim(uint32 chainId, address bridge) public returns (uint256 amount)

Claims funds from a bridge after they arrive

Decreases outstanding debt and deposits funds into yield pool

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Parameters

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Return Values

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sendFunds

function sendFunds(uint256 amount, address recipient) internal

Sends funds to a recipient

Handles both ERC20 and native currency transfers

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Parameters

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setTokenSwap

function setTokenSwap(address newTokenSwapAddress) external

Sets the token swap contract address

Used for swapping non-asset tokens received by the pool

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Parameters

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swapAndDeposit

function swapAndDeposit(address token, uint256 amount, uint24 uniswapWethPoolFeeToken, uint24 uniswapWethPoolFeeAsset, uint48 deadline, uint256 amountOutMinimum) public

Swaps tokens and deposits resulting assets

Swaps via Uniswap V3 through the token swap contract

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Parameters

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collectNonDepositedAssets

function collectNonDepositedAssets() public

Collects any assets not yet deposited and starts streaming them

Can be called by anyone to ensure timely asset collection

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beforeWithdraw

function beforeWithdraw(uint256 assets, uint256) internal

Hook called before withdrawing assets from the vault

Withdraws assets from yield pool before processing withdrawal

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Parameters

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afterDeposit

function afterDeposit(uint256 assets, uint256) internal

Hook called after depositing assets to the vault

Deposits assets into yield pool after receiving them

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Parameters

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processFailedHandler

function processFailedHandler(uint32 chainId, address bridge, bytes data) public

Processes failed Hyperlane messages manually

Only callable by owner, typically after slow bridge resolution

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Parameters

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receive

receive() external payable

Receives native currency

Required for WETH unwrapping in native currency pools