Add ERC7579 Executor modules

[ernestognw]

More generalized alternatives to #93 and #85

[ernestognw]

I changed the can* functions to internal _validate* functions, it keeps an internal interface for validation and is more consistent with the delayed executor.

Build is failing since the MultisigMocks need to be adapted, but it's still unclear how:

abstract contract ERC7579MultisigExecutorMock is ERC7579Executor, ERC7579Multisig, EIP712 {
    bytes32 private constant EXECUTE_OPERATION =
        keccak256("ExecuteOperation(address account,bytes32 mode,bytes executionCalldata,bytes32 salt)");

    function _validateExecution(
        address account,
        Mode mode,
        bytes calldata executionCalldata,
        bytes32 salt
    ) internal view virtual returns (bool) {
        // We're missing the `signature` here
        return _validateMultisignature(account, _getExecuteTypeHash(account, mode, executionCalldata, salt), signature);
    }

    function _getExecuteTypeHash(
        address account,
        Mode mode,
        bytes calldata executionCalldata,
        bytes32 salt
    ) internal view virtual returns (bytes32) {
        return
            _hashTypedDataV4(
                keccak256(abi.encode(EXECUTE_OPERATION, account, Mode.unwrap(mode), executionCalldata, salt))
            );
    }
}

For the modules to be successful, _validateExecution and _validateMultisignature must combine seamlessly.

[ernestognw]

I changed the can* functions to internal _validate* functions, it keeps an internal interface for validation and is more consistent with the delayed executor.

Build is failing since the MultisigMocks need to be adapted, but it's still unclear how:

// ...

For the modules to be successful, _validateExecution and _validateMultisignature must combine seamlessly.

Fixed by differentiating the data argument from the public schedule, execute and cancel functions and executeCalldata on their internal versions. The reasoning is that developers must override the public versions if they want to perform validation on data, slice it and extract the executeCalldata from there. This provides more flexibility and allows combining use cases as in the ERC7579MultisigMocks

[ernestognw]

Happy with the current design and it's good enough for the community version. Given the schedule, I think we should move on and merge so I can start writing ERC-7579 guides that include the social recovery use case. Also I should start playing around with this on Wizard.