Struct PoolRef 

pub struct PoolRef { /* private fields */ }

A reference to a Pool that can be shared across threads via cloning, along with the page size that will be used with it. Provides the API for interacting with the buffer pool in a thread-safe manner.

Implementations

impl PoolRef

pub fn new(page_size: NonZeroUsize, capacity: NonZeroUsize) -> Self

Returns a new PoolRef with the given page_size and capacity.

pub async fn next_id(&self) -> u64

Returns a unique id for the next blob that will use this buffer pool.

pub const fn offset_to_page(&self, offset: u64) -> (u64, usize)

Convert an offset into the number of the page it belongs to and the offset within that page.

pub async fn cache(&self, blob_id: u64, buf: &[u8], offset: u64) -> usize

Cache the provided slice of data in the buffer pool, returning the remaining bytes that didn’t fill a whole page. offset must be page aligned.

If the next page index would overflow u64, caching stops and the uncached bytes are returned. This can only occur with 1-byte pages on 64-bit architectures. On 32-bit architectures it cannot occur because the buffer length is bounded by usize::MAX (2^32-1), so even starting at page u64::MAX with 1-byte pages, at most 2^32-1 pages can be cached. On 64-bit architectures with page_size >= 2, the maximum starting page (u64::MAX / 2) plus maximum cacheable pages (usize::MAX / 2) equals u64::MAX - 1.

Panics

Panics if offset is not page aligned.

Trait Implementations

impl Clone for PoolRef

fn clone(&self) -> PoolRef

Returns a duplicate of the value.

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

Performs copy-assignment from source.