Method read_vectored_sync

block/src/lib.rs:456–493

(
        &mut self,
        offset: libc::off_t,
        iovecs: &[libc::iovec],
        user_data: u64,
        eventfd: &EventFd,
        completion_list: &mut VecDeque<(u64, i32)>,
    )

pub trait AsyncAdaptor {
    fn read_vectored_sync(
        &mut self,
        offset: libc::off_t,
        iovecs: &[libc::iovec],
        user_data: u64,
        eventfd: &EventFd,
        completion_list: &mut VecDeque<(u64, i32)>,
    ) -> AsyncIoResult<()>
    where
        Self: Read + Seek,
    {
        // Convert libc::iovec into IoSliceMut
        let mut slices: SmallVec<[IoSliceMut; DEFAULT_DESCRIPTOR_VEC_SIZE]> =
            SmallVec::with_capacity(iovecs.len());
        for iovec in iovecs.iter() {
            // SAFETY: on Linux IoSliceMut wraps around libc::iovec
            slices.push(IoSliceMut::new(unsafe {
                std::mem::transmute::<libc::iovec, &mut [u8]>(*iovec)
            }));
        }

        let result = {
            // Move the cursor to the right offset
            self.seek(SeekFrom::Start(offset as u64))
                .map_err(AsyncIoError::ReadVectored)?;

            let mut r = 0;
            for b in slices.iter_mut() {
                r += self.read(b).map_err(AsyncIoError::ReadVectored)?;
            }
            r
        };

        completion_list.push_back((user_data, result as i32));
        eventfd.write(1).unwrap();

        Ok(())
    }

    fn write_vectored_sync(
        &mut self,