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| 1 | +// SPDX-License-Identifier: UNLICENSED |
| 2 | +pragma solidity ^0.8.13; |
| 3 | + |
| 4 | +import {IWormholeRelayer} from "../interfaces/IWormholeRelayer.sol"; |
| 5 | +import {IWormholeReceiver} from "../interfaces/IWormholeReceiver.sol"; |
| 6 | + |
| 7 | +contract HelloWormhole is IWormholeReceiver { |
| 8 | + event GreetingReceived(string greeting, uint16 senderChain, address sender); |
| 9 | + |
| 10 | + uint256 constant GAS_LIMIT = 50_000; |
| 11 | + |
| 12 | + IWormholeRelayer public immutable wormholeRelayer; |
| 13 | + |
| 14 | + string public latestGreeting; |
| 15 | + |
| 16 | + constructor(address _wormholeRelayer) { |
| 17 | + wormholeRelayer = IWormholeRelayer(_wormholeRelayer); |
| 18 | + } |
| 19 | + |
| 20 | + function quoteCrossChainGreeting( |
| 21 | + uint16 targetChain |
| 22 | + ) public view returns (uint256 cost) { |
| 23 | + (cost, ) = wormholeRelayer.quoteEVMDeliveryPrice( |
| 24 | + targetChain, |
| 25 | + 0, |
| 26 | + GAS_LIMIT |
| 27 | + ); |
| 28 | + } |
| 29 | + |
| 30 | + function sendCrossChainGreeting( |
| 31 | + uint16 targetChain, |
| 32 | + address targetAddress, |
| 33 | + string memory greeting |
| 34 | + ) public payable { |
| 35 | + uint256 cost = quoteCrossChainGreeting(targetChain); |
| 36 | + require(msg.value == cost); |
| 37 | + wormholeRelayer.sendPayloadToEvm{value: cost}( |
| 38 | + targetChain, |
| 39 | + targetAddress, |
| 40 | + abi.encode(greeting, msg.sender), // payload |
| 41 | + 0, // no receiver value needed since we're just passing a message |
| 42 | + GAS_LIMIT |
| 43 | + ); |
| 44 | + } |
| 45 | + |
| 46 | + function receiveWormholeMessages( |
| 47 | + bytes memory payload, |
| 48 | + bytes[] memory, // additionalVaas |
| 49 | + bytes32, // address that called 'sendPayloadToEvm' (HelloWormhole contract address) |
| 50 | + uint16 sourceChain, |
| 51 | + bytes32 // unique identifier of delivery |
| 52 | + ) public payable override { |
| 53 | + require(msg.sender == address(wormholeRelayer), "Only relayer allowed"); |
| 54 | + |
| 55 | + // Parse the payload and do the corresponding actions! |
| 56 | + (string memory greeting, address sender) = abi.decode( |
| 57 | + payload, |
| 58 | + (string, address) |
| 59 | + ); |
| 60 | + latestGreeting = greeting; |
| 61 | + emit GreetingReceived(latestGreeting, sourceChain, sender); |
| 62 | + } |
| 63 | +} |
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