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Solidity API

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IRelayBridge

Interface for the RelayBridge contract

Defines the bridge function for cross-chain asset transfers

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bridge

function bridge(uint256 amount, address recipient, address poolAsset, uint256 poolGas, bytes extraData) external payable returns (uint256 nonce)

Bridges an asset (ERC20 token or native currency) from the origin chain to a pool chain

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Parameters

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Return Values

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RelayBridge

RelayBridge contract enabling cross-chain bridging via Hyperlane

Bridges assets from an origin chain to a configured pool chain

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BridgeTransaction

Internal struct capturing parameters for a bridge transaction

struct BridgeTransaction {
  uint256 amount;
  address recipient;
  address poolAsset;
  uint256 poolGas;
  bytes extraData;
  uint256 nonce;
  bytes txParams;
  uint32 poolChainId;
  bytes32 poolId;
}

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BridgingFailed

error BridgingFailed(uint256 nonce)

Error for failed bridging operations

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Parameters

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InsufficientValue

error InsufficientValue(uint256 received, uint256 expected)

Error for insufficient native value sent to cover fees or asset

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Parameters

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FailedFeeRefund

error FailedFeeRefund(uint256 value)

Error when refunding leftover native value fails

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Parameters

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transferNonce

uint256 transferNonce

Counter for assigning unique nonces to bridge transactions

Incremented with each bridge transaction to ensure uniqueness

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ASSET

address ASSET

Asset address on the origin chain being bridged (address(0) for native currency)

Immutable to ensure the bridge always handles the same asset

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BRIDGE_PROXY

contract BridgeProxy BRIDGE_PROXY

BridgeProxy contract handling origin-chain transfer logic

Uses delegatecall to execute custom bridge logic

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HYPERLANE_MAILBOX

address HYPERLANE_MAILBOX

Hyperlane Mailbox contract for cross-chain messaging

Used to dispatch messages to the pool chain

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BridgeInitiated

event BridgeInitiated(uint256 nonce, address sender, address recipient, address ASSET, address poolAsset, uint256 amount, contract BridgeProxy BRIDGE_PROXY)

Emitted when a bridge transaction is initiated on the origin chain

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Parameters

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BridgeExecuted

event BridgeExecuted(uint256 nonce)

Emitted after a bridge transaction is executed on the pool chain

This event would be emitted by the pool chain contract

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Parameters

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BridgeCancelled

event BridgeCancelled(uint256 nonce)

Emitted if a bridge transaction is cancelled prior to execution

This event would be emitted if a bridge is cancelled

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Parameters

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constructor

constructor(address asset, contract BridgeProxy bridgeProxy, address hyperlaneMailbox) public

Initializes the RelayBridge with asset and infrastructure contracts

All parameters are immutable after deployment

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Parameters

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getFee

function getFee(uint256 amount, address recipient, uint256 poolGas) external view returns (uint256 fee)

Calculates the fee required in native currency to dispatch a cross-chain message

Uses Hyperlane’s quoteDispatch to estimate the cross-chain messaging fee

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Parameters

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Return Values

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bridge

function bridge(uint256 amount, address recipient, address poolAsset, uint256 poolGas, bytes extraData) external payable returns (uint256 nonce)

Bridges an asset (ERC20 token or native currency) from the origin chain to a pool chain

_Executes a cross-chain bridge transaction with the following steps:

1. Validates sufficient payment for fees (and asset amount if native)
2. Transfers the asset from sender to this contract (if ERC20)
3. Executes bridge logic via delegatecall to BRIDGE_PROXY
4. Dispatches cross-chain message via Hyperlane
5. Refunds any excess native currency to sender_

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Parameters

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Return Values