Struct AlignedRegion 

pub struct AlignedRegion { /* private fields */ }

A page-aligned heap region. The buffer pool owns exactly one of these, which satisfies the alignment requirement of unbuffered I/O and the “allocate once, never free” requirement that keeps allocator retention out of the picture.

Implementations

impl AlignedRegion

pub fn new(len: usize) -> Result<Self>

pub unsafe fn page(&self, i: usize) -> &[u8]

Safety

No &mut to frame i may be live for the lifetime of the returned slice. The buffer pool guarantees this with its pin count; this type cannot.

pub unsafe fn page_mut(&self, i: usize) -> &mut [u8]

Safety

No other reference to frame i — shared or mutable — may be live for the lifetime of the returned slice.

This is deliberately an unsafe fn. As a safe fn, ordinary safe code could call it twice and hold two &mut [u8] over the same bytes, which is undefined behaviour however careful the pool is. A comment cannot make an unenforceable invariant sound; moving the obligation to the caller, in the type system, can.

pub unsafe fn prefix(&self, len: usize) -> &[u8]

A page-multiple prefix for one aligned multi-page I/O. The caller must enforce the same aliasing discipline as Self::page.

Trait Implementations

impl Drop for AlignedRegion

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl Send for AlignedRegion

impl Sync for AlignedRegion