8 use crate::syscall::SystemError;
78     fn open(&self, _data: &mut FilePrivateData, _mode: &FileMode) -> Result<(), SystemError> {  in open()  argument
79         Err(SystemError::EOPNOTSUPP_OR_ENOTSUP)  in open()
82     fn close(&self, _data: &mut FilePrivateData) -> Result<(), SystemError> {  in close()  argument
83         Err(SystemError::EOPNOTSUPP_OR_ENOTSUP)  in close()
86     fn metadata(&self) -> Result<Metadata, SystemError> {  in metadata()  argument
94     fn list(&self) -> Result<Vec<String>, SystemError> {  in list()  argument
95         Err(SystemError::EOPNOTSUPP_OR_ENOTSUP)  in list()
98     fn set_metadata(&self, metadata: &Metadata) -> Result<(), SystemError> {  in set_metadata()  argument
110     fn poll(&self) -> Result<PollStatus, SystemError> {  in poll()  argument
121     ) -> Result<usize, SystemError> {  in read_at()  argument
123             return Err(SystemError::EINVAL);  in read_at()
130         return Err(SystemError::EINVAL);  in read_at()
140     ) -> Result<usize, SystemError> {  in write_at()  argument
142             return Err(SystemError::EINVAL);  in write_at()
149         return Err(SystemError::EINVAL);  in write_at()