Struct OverflowChain 

pub struct OverflowChain<'p> { /* private fields */ }

Chain operations over a pager.

Held by value rather than as impl Pager methods to keep overflow concerns out of engine::pager. Slice E will hold one of these from inside the B-tree write path.

Implementations

impl<'p> OverflowChain<'p>

pub fn new(pager: &'p Pager) -> OverflowChain<'p>

pub fn store(&self, bytes: &[u8]) -> Result<(u32, u64), OverflowError>

Allocate enough overflow pages to hold bytes, link them, and return the head page id together with the total length.

Empty input still produces a single zero-length head page so that the leaf-side pointer is always valid.

pub fn read( &self, head_page_id: u32, total_len: u64, ) -> Result<Vec<u8>, OverflowError>

Walk the chain and return the concatenated payload.

total_len must match the actual bytes carried by the chain; if it does not, a LengthMismatch error is returned (no truncation, no silent extension).

pub fn free(&self, head_page_id: u32) -> Result<(), OverflowError>

Walk the chain starting at head_page_id and return every page to the free list.