Struct glommio::io::OpenOptions

pub struct OpenOptions { /* fields omitted */ }

Options and flags which can be used to configure how a file is opened.

This builder exposes the ability to configure how a DmaFile is opened and what operations are permitted on the open file. The DmaFile::open and DmaFile::create methods are aliases for commonly used options using this builder.

Implementations

impl OpenOptions

pub fn new() -> Self

Creates a blank new set of options ready for configuration.

All options are initially set to false.

pub fn read(&mut self, read: bool) -> &mut Self

Sets the option for read access.

This option, when true, will indicate that the file should be read-able if opened.

pub fn write(&mut self, write: bool) -> &mut Self

Sets the option for write access.

This option, when true, will indicate that the file should be write-able if opened.

If the file already exists, any write calls on it will overwrite its contents, without truncating it.

pub fn append(&mut self, append: bool)

Sets the option for appending a previous file.

If a file is successfully opened with this option set it will append new data at the end of it.

The file must be opened with write access for append to work.

pub fn truncate(&mut self, truncate: bool) -> &mut Self

Sets the option for truncating a previous file.

If a file is successfully opened with this option set it will truncate the file to 0 length if it already exists.

The file must be opened with write access for truncate to work.

pub fn create(&mut self, create: bool) -> &mut Self

Sets the option to create a new file, or open it if it already exists.

In order for the file to be created, OpenOptions::write access must be used.

pub fn create_new(&mut self, create_new: bool) -> &mut Self

Sets the option to create a new file, failing if it already exists.

No file is allowed to exist at the target location, also no (dangling) symlink. In this way, if the call succeeds, the file returned is guaranteed to be new.

This option is useful because it is atomic. Otherwise between checking whether a file exists and creating a new one, the file may have been created by another process (a TOCTOU race condition / attack).

If .create_new(true) is set, .create() and .truncate() are ignored.

The file must be opened with write or append access in order to create a new file.

pub fn custom_flags(&mut self, flags: i32) -> &mut Self

Pass custom flags to the flags argument of open_at.

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

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

pub async fn dma_open<P: AsRef<Path>>(&self, path: P) -> Result<DmaFile, ()>

Similiar to OpenOptions::open() in the standard library, but returns a DMA file

pub async fn buffered_open<P: AsRef<Path>>(
    &self,
    path: P
) -> Result<BufferedFile, ()>

Similiar to OpenOptions::open() in the standard library, but returns a Buffered file

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.

impl Default for OpenOptions

fn default() -> Self

Returns the “default value” for a type.