Struct CalculatedPageStates 

pub struct CalculatedPageStates { /* private fields */ }

A cache that uses knowledge about the typical layout of pages.

Use the ArrayPageStates cache or HeapPageStates cache when you have fewer than ~32 pages.

The layout is always as follows:

• X amount of closed pages
• Y amount of open pages
  • Y is at least 1
  • One of the open pages may be partial
• If a partial page is present, it’s in the order ascending page indices: Closed -> Partial -> Open

The idea is to have an anchor which is the first open page (which may be the partial open page) and then keep track of the amount of open pages in front and the amount of closed pages behind it.

We know the anchor for sure when we find a partial open page. Since sequential-storage always iterates going forward and never back, we can have a ‘guessed’ anchor if we find the first open page. But when the anchor is guessed, we need to be a little pessimistic.

Thus, this cache isn’t able to remember every page state in every situation, but this is only the case when the anchor hasn’t been found yet. When the cache is fully warm, it does have perfect knowledge.

We don’t have to care about corruption, because when corruption is repaired the cache is invalidated.

Implementations

impl CalculatedPageStates

pub const fn new(page_count: usize) -> Self

Create a new empty cache for the amount of pages

Trait Implementations

impl Debug for CalculatedPageStates

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PageStatesCache for CalculatedPageStates