Struct ShadowFile 

pub struct ShadowFile { /* private fields */ }

Manages shadow pages for copy-on-write during a transaction.

Implementations

impl ShadowFile

pub fn new() -> Self

pub fn set_file_name(&mut self, name: &str)

Set the BufferManager file name that this shadow file tracks.

pub fn create_shadow(&mut self, page_id: u64, data: Vec<u8>)

pub fn get_shadow(&self, page_id: u64) -> Option<&ShadowEntry>

pub fn has_shadow(&self, page_id: u64) -> bool

pub fn len(&self) -> usize

Number of shadow entries.

pub fn is_empty(&self) -> bool

pub fn clear(&mut self)

Clear all shadow entries (used during rollback to discard changes).

pub fn apply(&self, buffer_manager: &Arc<Mutex<BufferManager>>) -> Result<()>

Apply all dirty shadow pages to the BufferManager.

For each shadow entry, pins the page, writes the shadow data, marks it dirty, and unpins. This makes the transaction’s writes visible.

Call this on commit after the WAL has been flushed.

pub fn discard(&mut self)

Discard all shadow entries (rollback).

Simply clears the entries — the original pages in the BufferManager were never modified, so no undo is needed at the page level.

pub fn dirty_pages(&self) -> impl Iterator<Item = &ShadowEntry>

Trait Implementations

impl Debug for ShadowFile

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

Formats the value using the given formatter.

impl Default for ShadowFile

fn default() -> ShadowFile

Returns the “default value” for a type.