Struct a10::fs::OpenOptions

pub struct OpenOptions { /* private fields */ }

Options used to configure how a file (AsyncFd) is opened.

Implementations

impl OpenOptions

pub const fn new() -> OpenOptions

Empty OpenOptions, has reading enabled by default.

pub const fn read(self) -> Self

Enable read access.

Note that read access is already enabled by default, so this is only useful if you called OpenOptions::write_only and want to enable read access as well.

pub const fn write(self) -> Self

Enable write access.

pub const fn write_only(self) -> Self

Only enable write access, disabling read access.

pub const fn append(self) -> Self

Set writing to append only mode.

Notes

This requires writing access to be enabled.

pub const fn truncate(self) -> Self

Truncate the file if it exists.

pub const fn create(self) -> Self

If the file doesn’t exist create it.

pub const fn create_new(self) -> Self

Force a file to be created, failing if a file already exists.

This options implies OpenOptions::create.

pub const fn data_sync(self) -> Self

Write operations on the file will complete according to the requirements of synchronized I/O data integrity completion.

By the time write(2) (and similar) return, the output data has been transferred to the underlying hardware, along with any file metadata that would be required to retrieve that data (i.e., as though each write(2) was followed by a call to fdatasync(2)).

pub const fn sync(self) -> Self

Write operations on the file will complete according to the requirements of synchronized I/O file integrity completion (by contrast with the synchronized I/O data integrity completion provided by OpenOptions::data_sync.)

By the time write(2) (or similar) returns, the output data and associated file metadata have been transferred to the underlying hardware (i.e., as though each write(2) was followed by a call to fsync(2)).

pub const fn direct(self) -> Self

Try to minimize cache effects of the I/O to and from this file.

File I/O is done directly to/from user-space buffers. This uses the O_DIRECT flag which on its own makes an effort to transfer data synchronously, but does not give the guarantees of the O_SYNC flag (OpenOptions::sync) that data and necessary metadata are transferred. To guarantee synchronous I/O, O_SYNC must be used in addition to O_DIRECT.

pub const fn mode(self, mode: mode_t) -> Self

Sets the mode bits that a new file will be created with.

pub fn open_temp_file(self, sq: SubmissionQueue, dir: PathBuf) -> Open

Create an unnamed temporary regular file. The dir argument specifies a directory; an unnamed inode will be created in that directory’s filesystem. Anything written to the resulting file will be lost when the last file descriptor is closed, unless the file is given a name.

OpenOptions::write must be set. The linkat(2) system call can be used to make the temporary file permanent.

pub fn open(self, sq: SubmissionQueue, path: PathBuf) -> Open

Open path.

Trait Implementations

impl Clone for OpenOptions

fn clone(&self) -> OpenOptions

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for OpenOptions

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.