Trait IoBufMut

pub trait IoBufMut: IoBuf + SetLen {
    // Required method
    fn as_uninit(&mut self) -> &mut [MaybeUninit<u8>];

    // Provided methods
    fn buf_capacity(&mut self) -> usize { ... }
    fn buf_mut_ptr(&mut self) -> *mut MaybeUninit<u8> { ... }
    fn as_mut_slice(&mut self) -> &mut [u8] ⓘ { ... }
    fn reserve(&mut self, len: usize) -> Result<(), ReserveError> { ... }
    fn reserve_exact(&mut self, len: usize) -> Result<(), ReserveExactError> { ... }
    fn uninit(self) -> Uninit<Self>
       where Self: Sized { ... }
    fn is_filled(&mut self) -> bool { ... }
}

Expand description

A trait for mutable buffers.

The IoBufMut trait is implemented by buffer types that can be passed to mutable completion-based IO operations, like reading content from a file and write to the buffer. This trait will take all space of a buffer into account, including uninitialized bytes.

Required Methods§

fn as_uninit(&mut self) -> &mut [MaybeUninit<u8>]

Get the full mutable slice of the buffer, including both initialized and uninitialized bytes.

Provided Methods§

fn buf_capacity(&mut self) -> usize

Total capacity of the buffer, including both initialized and uninitialized bytes.

fn buf_mut_ptr(&mut self) -> *mut MaybeUninit<u8>

Get the raw mutable pointer to the buffer.

fn as_mut_slice(&mut self) -> &mut [u8] ⓘ

Get the mutable slice of initialized bytes. The content is the same as IoBuf::as_init, but mutable.

fn reserve(&mut self, len: usize) -> Result<(), ReserveError>

Reserve additional capacity for the buffer.

This is a no-op by default. Types that support dynamic resizing (like Vec<u8>) will override this method to actually reserve capacity. The return value indicates whether the reservation succeeded. See ReserveError for details.

fn reserve_exact(&mut self, len: usize) -> Result<(), ReserveExactError>

Reserve exactly len additional capacity for the buffer.

By default this falls back to IoBufMut::reserve, which is a no-op for most types. Types that support dynamic resizing (like Vec<u8>) will override this method to actually reserve capacity. The return value indicates whether the exact reservation succeeded. See ReserveExactError for details.

fn uninit(self) -> Uninit<Self>
where Self: Sized,

Returns an Uninit, which is a Slice that only exposes uninitialized bytes.

It will always point to the uninitialized area of a IoBufMut even after reading in some bytes, which is done by SetLen. This is useful for writing data into buffer without overwriting any existing bytes.

§Examples

use compio_buf::{IoBuf, IoBufMut};

let mut buf = Vec::from(b"hello world");
buf.reserve_exact(10);
let mut slice = buf.uninit();

assert_eq!(slice.as_init(), b"");
assert_eq!(slice.buf_capacity(), 10);