// SPDX-License-Identifier: Apache-2.0 pragma solidity >=0.8.0; import "@openzeppelin/contracts/token/ERC20/extensions/ERC4626.sol"; import {TokenMessage} from "../libs/TokenMessage.sol"; import {HypERC20Collateral} from "../HypERC20Collateral.sol"; import {TypeCasts} from "../../libs/TypeCasts.sol"; /** * @title Hyperlane ERC4626 Token Collateral with deposits collateral to a vault * @author Abacus Works */ contract HypERC4626Collateral is HypERC20Collateral { using TypeCasts for address; using TokenMessage for bytes; using Math for uint256; // Address of the ERC4626 compatible vault ERC4626 public immutable vault; uint256 public constant PRECISION = 1e10; bytes32 public constant NULL_RECIPIENT = 0x0000000000000000000000000000000000000000000000000000000000000001; constructor( ERC4626 _vault, address _mailbox ) HypERC20Collateral(_vault.asset(), _mailbox) { vault = _vault; } function initialize( address _hook, address _interchainSecurityModule, address _owner ) public override initializer { _MailboxClient_initialize(_hook, _interchainSecurityModule, _owner); } function _transferRemote( uint32 _destination, bytes32 _recipient, uint256 _amount, uint256 _value, bytes memory _hookMetadata, address _hook ) internal virtual override returns (bytes32 messageId) { // Can't override _transferFromSender only because we need to pass shares in the token message _transferFromSender(_amount); uint256 _shares = _depositIntoVault(_amount); uint256 _exchangeRate = PRECISION.mulDiv( vault.totalAssets(), vault.totalSupply(), Math.Rounding.Down ); bytes memory _tokenMetadata = abi.encode(_exchangeRate); bytes memory _tokenMessage = TokenMessage.format( _recipient, _shares, _tokenMetadata ); messageId = _Router_dispatch( _destination, _value, _tokenMessage, _hookMetadata, _hook ); emit SentTransferRemote(_destination, _recipient, _shares); } /** * @dev Deposits into the vault and increment assetDeposited * @param _amount amount to deposit into vault */ function _depositIntoVault(uint256 _amount) internal returns (uint256) { wrappedToken.approve(address(vault), _amount); return vault.deposit(_amount, address(this)); } /** * @dev Transfers `_amount` of `wrappedToken` from this contract to `_recipient`, and withdraws from vault * @inheritdoc HypERC20Collateral */ function _transferTo( address _recipient, uint256 _amount, bytes calldata ) internal virtual override { // withdraw with the specified amount of shares vault.redeem(_amount, _recipient, address(this)); } /** * @dev Update the exchange rate on the synthetic token by accounting for additional yield accrued to the underlying vault * @param _destinationDomain domain of the vault */ function rebase(uint32 _destinationDomain) public payable { // force a rebase with an empty transfer to 0x1 _transferRemote( _destinationDomain, NULL_RECIPIENT, 0, msg.value, bytes(""), address(0) ); } }