Struct File 

pub struct File { /* private fields */ }

Available on crate feature fs only.

A reference to an open file on the filesystem.

An instance of a File can be read and/or written depending on what options it was opened with. The File type provides positional read and write operations. The file does not maintain an internal cursor. The caller is required to specify an offset when issuing an operation.

If you’d like to use methods from AsyncRead or AsyncWrite traits, you can wrap File with std::io::Cursor.

Examples

use compio::fs::File;
use compio::buf::BufResult;
use std::io::Cursor;

let file = File::open("foo.txt").await?;
let cursor = Cursor::new(file);

let int = cursor.read_u32().await?;
let float = cursor.read_f32().await?;

let mut string = String::new();
let BufResult(result, string) = cursor.read_to_string(string).await;

let mut buf = vec![0; 1024];
let BufResult(result, buf) = cursor.read_exact(buf).await;

Implementations

impl File

pub async fn open(path: impl AsRef<Path>) -> Result<File, Error>

Attempts to open a file in read-only mode.

See the OpenOptions::open method for more details.

pub async fn create(path: impl AsRef<Path>) -> Result<File, Error>

Opens a file in write-only mode.

This function will create a file if it does not exist, and will truncate it if it does.

See the OpenOptions::open function for more details.

pub fn close(self) -> impl Future<Output = Result<(), Error>>

Close the file. If the returned future is dropped before polling, the file won’t be closed.

pub async fn set_len(&self, size: u64) -> Result<(), Error>

Available on Unix only.

Truncates or extends the underlying file, updating the size of this file to become size.

NOTE: On Linux kernel <= 6.9 or when io uring is disabled, the operation will be offloaded to the separate blocking thread

pub async fn metadata(&self) -> Result<Metadata, Error>

Available on Unix only.

Queries metadata about the underlying file.

pub async fn set_permissions(&self, perm: Permissions) -> Result<(), Error>

Changes the permissions on the underlying file.

pub async fn sync_all(&self) -> Result<(), Error>

Attempts to sync all OS-internal metadata to disk.

This function will attempt to ensure that all in-memory data reaches the filesystem before returning.

pub async fn sync_data(&self) -> Result<(), Error>

This function is similar to sync_all, except that it might not synchronize file metadata to the filesystem.

This is intended for use cases that must synchronize content, but don’t need the metadata on disk. The goal of this method is to reduce disk operations.

Note that some platforms may simply implement this in terms of sync_all.

Trait Implementations

impl AsFd for File

Available on Unix only.

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor.

impl AsRawFd for File

fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor.

impl AsyncReadAt for File

async fn read_at<T>(&self, buffer: T, pos: u64) -> BufResult<usize, T>

where T: IoBufMut,

Like AsyncRead::read, except that it reads at a specified position.

async fn read_vectored_at<T>(&self, buffer: T, pos: u64) -> BufResult<usize, T>

where T: IoVectoredBufMut,

Like AsyncRead::read_vectored, except that it reads at a specified position.

impl AsyncReadManagedAt for File

type Buffer<'a> = BorrowedBuffer<'a>

Filled buffer type

type BufferPool = BufferPool

Buffer pool type

async fn read_managed_at<'a>( &self, buffer_pool: &'a <File as AsyncReadManagedAt>::BufferPool, len: usize, pos: u64, ) -> Result<<File as AsyncReadManagedAt>::Buffer<'a>, Error>

Read some bytes from this source at position with Self::BufferPool and return a Self::Buffer.

impl AsyncWriteAt for &File

async fn write_at<T>(&mut self, buffer: T, pos: u64) -> BufResult<usize, T>

where T: IoBuf,

Like AsyncWrite::write, except that it writes at a specified position.

async fn write_vectored_at<T>( &mut self, buffer: T, pos: u64, ) -> BufResult<usize, T>

where T: IoVectoredBuf,

Like AsyncWrite::write_vectored, except that it writes at a specified position.

impl AsyncWriteAt for File

async fn write_at<T>(&mut self, buf: T, pos: u64) -> BufResult<usize, T>

where T: IoBuf,

Like AsyncWrite::write, except that it writes at a specified position.

async fn write_vectored_at<T>( &mut self, buf: T, pos: u64, ) -> BufResult<usize, T>

where T: IoVectoredBuf,

Like AsyncWrite::write_vectored, except that it writes at a specified position.

impl Clone for File

fn clone(&self) -> File

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for File

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

Formats the value using the given formatter.

impl FromRawFd for File

Available on Unix only.

unsafe fn from_raw_fd(fd: i32) -> File

Constructs a new instance of Self from the given raw file descriptor.

impl Splittable for &File

type ReadHalf = File

The type of the read half, which normally implements AsyncRead or AsyncReadAt.

type WriteHalf = File

The type of the write half, which normally implements AsyncWrite or AsyncWriteAt.

fn split( self, ) -> (<&File as Splittable>::ReadHalf, <&File as Splittable>::WriteHalf)

Consumes self and returns a tuple containing separate read and write halves.

impl Splittable for File

type ReadHalf = File

The type of the read half, which normally implements AsyncRead or AsyncReadAt.

type WriteHalf = File

The type of the write half, which normally implements AsyncWrite or AsyncWriteAt.

fn split( self, ) -> (<File as Splittable>::ReadHalf, <File as Splittable>::WriteHalf)

Consumes self and returns a tuple containing separate read and write halves.

impl ToSharedFd<File> for File

fn to_shared_fd(&self) -> SharedFd<File>

Return a cloned SharedFd.