[ERC6981] 予約型スマートアカウントの仕組みを理解しよう！

interface IAccountRegistry {
    /**
     * @dev Registry instances emit the AccountCreated event upon successful account creation
     */
    event AccountCreated(address account, address accountImplementation, uint256 salt);

    /**
     * @dev Registry instances emit the AccountClaimed event upon successful claim of account by owner
     */
    event AccountClaimed(address account, address owner);

    /**
     * @dev Creates a smart contract account.
     *
     * If account has already been created, returns the account address without calling create2.
     *
     * @param salt       - The identifying salt for which the user wishes to deploy an Account Instance
     *
     * Emits AccountCreated event
     * @return the address for which the Account Instance was created
     */
    function createAccount(uint256 salt) external returns (address);

    /**
     * @dev Allows an owner to claim a smart contract account created by this registry.
     *
     * If the account has not already been created, the account will be created first using `createAccount`
     *
     * @param owner      - The initial owner of the new Account Instance
     * @param salt       - The identifying salt for which the user wishes to deploy an Account Instance
     * @param expiration - If expiration > 0, represents expiration time for the signature.  Otherwise
     *                     signature does not expire.
     * @param message    - The keccak256 message which validates the owner, salt, expiration
     * @param signature  - The signature which validates the owner, salt, expiration
     *
     * Emits AccountClaimed event
     * @return the address of the claimed Account Instance
     */
    function claimAccount(
        address owner,
        uint256 salt,
        uint256 expiration,
        bytes32 message,
        bytes calldata signature
    ) external returns (address);

    /**
     * @dev Returns the computed address of a smart contract account for a given identifying salt
     *
     * @return the computed address of the account
     */
    function account(uint256 salt) external view returns (address);

    /**
     * @dev Fallback signature verification for unclaimed accounts
     */
    function isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4);
}

event AccountCreated(address account, address accountImplementation, uint256 salt);

event AccountClaimed(address account, address owner);

function createAccount(uint256 salt) external returns (address);

function claimAccount(
    address owner,
    uint256 salt,
    uint256 expiration,
    bytes32 message,
    bytes calldata signature
) external returns (address);

function account(uint256 salt) external view returns (address);

function isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4);

interface IAccount is IERC1271 {
    /**
     * @dev Sets the owner of the Account Instance.
     *
     * Only callable by the current owner of the instance, or by the registry if the Account
     * Instance has not yet been claimed.
     *
     * @param owner      - The new owner of the Account Instance
     */
    function setOwner(address owner) external;
}

function setOwner(address owner) external;

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.13;

/// @author: manifold.xyz

import {Create2} from "openzeppelin/utils/Create2.sol";

import {Address} from "../../lib/Address.sol";
import {ERC1167ProxyBytecode} from "../../lib/ERC1167ProxyBytecode.sol";
import {IAccountRegistryFactory} from "./IAccountRegistryFactory.sol";

contract AccountRegistryFactory is IAccountRegistryFactory {
    using Address for address;

    error InitializationFailed();

    address private immutable registryImplementation = 0x076B08EDE2B28fab0c1886F029cD6d02C8fF0E94;

    function createRegistry(
        uint96 index,
        address accountImplementation,
        bytes calldata accountInitData
    ) external returns (address) {
        bytes32 salt = _getSalt(msg.sender, index);
        bytes memory code = ERC1167ProxyBytecode.createCode(registryImplementation);
        address _registry = Create2.computeAddress(salt, keccak256(code));

        if (_registry.isDeployed()) return _registry;

        _registry = Create2.deploy(0, salt, code);

        (bool success, ) = _registry.call(
            abi.encodeWithSignature(
                "initialize(address,address,bytes)",
                msg.sender,
                accountImplementation,
                accountInitData
            )
        );
        if (!success) revert InitializationFailed();

        emit AccountRegistryCreated(_registry, accountImplementation, index);

        return _registry;
    }

    function registry(address deployer, uint96 index) external view override returns (address) {
        bytes32 salt = _getSalt(deployer, index);
        bytes memory code = ERC1167ProxyBytecode.createCode(registryImplementation);
        return Create2.computeAddress(salt, keccak256(code));
    }

    function _getSalt(address deployer, uint96 index) private pure returns (bytes32) {
        return bytes32(abi.encodePacked(deployer, index));
    }
}

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.13;

/// @author: manifold.xyz

import {Create2} from "openzeppelin/utils/Create2.sol";
import {ECDSA} from "openzeppelin/utils/cryptography/ECDSA.sol";
import {Ownable} from "openzeppelin/access/Ownable.sol";
import {Initializable} from "openzeppelin/proxy/utils/Initializable.sol";
import {IERC1271} from "openzeppelin/interfaces/IERC1271.sol";
import {SignatureChecker} from "openzeppelin/utils/cryptography/SignatureChecker.sol";

import {Address} from "../../lib/Address.sol";
import {IAccountRegistry} from "../../interfaces/IAccountRegistry.sol";
import {ERC1167ProxyBytecode} from "../../lib/ERC1167ProxyBytecode.sol";

contract AccountRegistryImplementation is Ownable, Initializable, IAccountRegistry {
    using Address for address;
    using ECDSA for bytes32;

    struct Signer {
        address account;
        bool isContract;
    }

    error InitializationFailed();
    error ClaimFailed();
    error Unauthorized();

    address public accountImplementation;
    bytes public accountInitData;
    Signer public signer;

    constructor() {
        _disableInitializers();
    }

    function initialize(
        address owner,
        address accountImplementation_,
        bytes calldata accountInitData_
    ) external initializer {
        _transferOwnership(owner);
        accountImplementation = accountImplementation_;
        accountInitData = accountInitData_;
    }

    /**
     * @dev See {IAccountRegistry-createAccount}
     */
    function createAccount(uint256 salt) external override returns (address) {
        bytes memory code = ERC1167ProxyBytecode.createCode(accountImplementation);
        address _account = Create2.computeAddress(bytes32(salt), keccak256(code));

        if (_account.isDeployed()) return _account;

        _account = Create2.deploy(0, bytes32(salt), code);

        (bool success, ) = _account.call(accountInitData);
        if (!success) revert InitializationFailed();

        emit AccountCreated(_account, accountImplementation, salt);

        return _account;
    }

    /**
     * @dev See {IAccountRegistry-claimAccount}
     */
    function claimAccount(
        address owner,
        uint256 salt,
        uint256 expiration,
        bytes32 message,
        bytes calldata signature
    ) external override returns (address) {
        _verify(owner, salt, expiration, message, signature);
        address _account = this.createAccount(salt);

        (bool success, ) = _account.call(
            abi.encodeWithSignature("transferOwnership(address)", owner)
        );
        if (!success) revert ClaimFailed();

        emit AccountClaimed(_account, owner);
        return _account;
    }

    /**
     * @dev See {IAccountRegistry-account}
     */
    function account(uint256 salt) external view override returns (address) {
        bytes memory code = ERC1167ProxyBytecode.createCode(accountImplementation);
        return Create2.computeAddress(bytes32(salt), keccak256(code));
    }

    /**
     * @dev See {IAccountRegistry-isValidSignature}
     */
    function isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4) {
        bytes32 expectedHash = keccak256(abi.encodePacked(hash, msg.sender));
        bool isValid = SignatureChecker.isValidSignatureNow(
            signer.account,
            expectedHash,
            signature
        );
        if (isValid) {
            return IERC1271.isValidSignature.selector;
        }

        return "";
    }

    function updateSigner(address newSigner) external onlyOwner {
        uint32 signerSize;
        assembly {
            signerSize := extcodesize(newSigner)
        }
        signer.account = newSigner;
        signer.isContract = signerSize > 0;
    }

    function _verify(
        address owner,
        uint256 salt,
        uint256 expiration,
        bytes32 message,
        bytes calldata signature
    ) internal view {
        address signatureAccount;

        if (signer.isContract) {
            if (!SignatureChecker.isValidSignatureNow(signer.account, message, signature))
                revert Unauthorized();
        } else {
            signatureAccount = message.recover(signature);
        }

        bytes32 expectedMessage = keccak256(
            abi.encodePacked("\x19Ethereum Signed Message:\n84", owner, salt, expiration)
        );

        if (
            message != expectedMessage ||
            (!signer.isContract && signatureAccount != signer.account) ||
            (expiration != 0 && expiration < block.timestamp)
        ) revert Unauthorized();
    }
}

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.13;

/// @author: manifold.xyz

import {IERC1271} from "openzeppelin/interfaces/IERC1271.sol";
import {SignatureChecker} from "openzeppelin/utils/cryptography/SignatureChecker.sol";
import {IERC165} from "openzeppelin/utils/introspection/IERC165.sol";
import {ERC165Checker} from "openzeppelin/utils/introspection/ERC165Checker.sol";
import {IERC721} from "openzeppelin/token/ERC721/IERC721.sol";
import {IERC721Receiver} from "openzeppelin/token/ERC721/IERC721Receiver.sol";
import {IERC1155Receiver} from "openzeppelin/token/ERC1155/IERC1155Receiver.sol";
import {Initializable} from "openzeppelin/proxy/utils/Initializable.sol";
import {Ownable} from "openzeppelin/access/Ownable.sol";
import {IERC1967Account} from "./IERC1967Account.sol";

import {IAccount} from "../../interfaces/IAccount.sol";

/**
 * @title ERC1967AccountImplementation
 * @notice A lightweight, upgradeable smart contract wallet implementation
 */
contract ERC1967AccountImplementation is
    IAccount,
    IERC165,
    IERC721Receiver,
    IERC1155Receiver,
    IERC1967Account,
    Initializable,
    Ownable
{
    address public registry;

    constructor() {
        _disableInitializers();
    }

    function initialize() external initializer {
        registry = msg.sender;
        _transferOwnership(registry);
    }

    function supportsInterface(bytes4 interfaceId) external pure returns (bool) {
        return (interfaceId == type(IAccount).interfaceId ||
            interfaceId == type(IERC1967Account).interfaceId ||
            interfaceId == type(IERC1155Receiver).interfaceId ||
            interfaceId == type(IERC721Receiver).interfaceId ||
            interfaceId == type(IERC165).interfaceId);
    }

    function onERC721Received(
        address,
        address,
        uint256,
        bytes memory
    ) public pure returns (bytes4) {
        return this.onERC721Received.selector;
    }

    function onERC1155Received(
        address,
        address,
        uint256,
        uint256,
        bytes memory
    ) public pure returns (bytes4) {
        return this.onERC1155Received.selector;
    }

    function onERC1155BatchReceived(
        address,
        address,
        uint256[] memory,
        uint256[] memory,
        bytes memory
    ) public pure returns (bytes4) {
        return this.onERC1155BatchReceived.selector;
    }

    /**
     * @dev {See IERC1967Account-executeCall}
     */
    function executeCall(
        address _target,
        uint256 _value,
        bytes calldata _data
    ) external payable override onlyOwner returns (bytes memory _result) {
        bool success;
        // solhint-disable-next-line avoid-low-level-calls
        (success, _result) = _target.call{value: _value}(_data);
        require(success, string(_result));
        emit TransactionExecuted(_target, _value, _data);
        return _result;
    }

    /**
     * @dev {See IAccount-setOwner}
     */
    function setOwner(address _owner) external override onlyOwner {
        _transferOwnership(_owner);
    }

    receive() external payable {}

    function isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4) {
        if (owner() == registry) {
            return IERC1271(registry).isValidSignature(hash, signature);
        }

        bool isValid = SignatureChecker.isValidSignatureNow(owner(), hash, signature);
        if (isValid) {
            return IERC1271.isValidSignature.selector;
        }

        return "";
    }
}