Struct read_write_at::DerefWrapper

pub struct DerefWrapper<T: DerefMut>(pub T);

A wrapper struct to allow accessing RefCell and Mutex helper impls for trait objects.

Example:

use read_write_at::{ReadWriteSeek,ReadWriteAtMut,ReadWriteAt,DerefWrapper};
 
let v = vec![3u8, 4,5,6];
let c = std::io::Cursor::new(v);
let rws = ReadWriteSeek(c);
let obj1 : Box<dyn ReadWriteAtMut> = Box::new(rws);
let mtx = std::sync::Mutex::new(DerefWrapper(obj1));
let obj2 : Box<dyn ReadWriteAt> = Box::new(mtx);
 
let mut v2 = vec![0,0];
obj2.read_exact_at(&mut v2[..], 1).unwrap();
assert_eq!(v2, vec![4,5]);

Trait Implementations

impl<T: ?Sized, U> ReadAtMut for DerefWrapper<U> where
    T: ReadAtMut,
    U: DerefMut<Target = T>, 

fn read_at(&mut self, buf: &mut [u8], offset: u64) -> Result<usize>

Similar to ReadAt::read_at, but it is allowed to change object internal state.

fn read_exact_at(&mut self, buf: &mut [u8], offset: u64) -> Result<()>

Similar to read_at, but without short reads.

impl<T: ?Sized, U> WriteAtMut for DerefWrapper<U> where
    T: WriteAtMut,
    U: DerefMut<Target = T>, 

fn write_at(&mut self, buf: &[u8], offset: u64) -> Result<usize>

Writes a number of bytes starting from a given offset. Returns the number of bytes written. The offset is relative to the start of the (virtual) file and thus independent from the current cursor, if the object has concept of a cursor. That cursor then should not be affected by this function. Short writes are not considered as errors.

fn write_all_at(&mut self, buf: &[u8], offset: u64) -> Result<()>

Similar to write_at, but without short writes. if entirety of the provided buffer cannot be written, an error is returned.