Struct PageAllocator 

pub struct PageAllocator { /* private fields */ }

In-memory page allocator state.

Implementations

impl PageAllocator

pub fn new(high_water_mark: u32) -> Self

Create a new allocator starting from the given high water mark.

pub fn allocate(&mut self) -> PageId

Allocate a new page ID. Prefers reusing reclaimed pages; falls back to incrementing the high water mark.

pub fn free(&mut self, page_id: PageId)

Mark a page as freed in the current transaction. The page is NOT immediately reusable — it goes into the pending-free list.

pub fn high_water_mark(&self) -> u32

Current high water mark (next page ID that would be allocated from disk).

pub fn freed_this_txn(&self) -> &[PageId]

Pages freed in the current transaction.

pub fn add_ready_to_use(&mut self, pages: Vec<PageId>)

Add pages that are safe to reuse (reclaimed from pending-free chain).

pub fn commit(&mut self) -> Vec<PageId>

Commit: take ownership of freed pages (for writing to pending-free chain). Returns the list of pages freed in this transaction.

pub fn rollback(&mut self)

Rollback: discard freed pages (transaction aborted).

pub fn ready_count(&self) -> usize

Number of pages available for immediate reuse.

pub fn freed_count(&self) -> usize

Number of pages freed in the current transaction.