Struct Journal 

pub struct Journal { /* private fields */ }

A journal that records operations for undo/redo support.

Implementations

impl Journal

pub fn new() -> Self

Create a new empty journal with recording enabled.

pub fn start_recording(&mut self)

Start recording operations.

pub fn stop_recording(&mut self)

Stop recording operations.

pub fn is_recording(&self) -> bool

Whether recording is active.

pub fn record(&mut self, op: Operation)

Record an operation. Clears the redo stack.

pub fn can_undo(&self) -> bool

Whether undo is available.

pub fn can_redo(&self) -> bool

Whether redo is available.

pub fn undo(&mut self) -> Option<Operation>

Pop the last operation for undoing. Returns the operation to undo. The caller is responsible for applying the inverse.

pub fn redo(&mut self) -> Option<Operation>

Pop the last undone operation for redoing.

pub fn inverse(op: &Operation) -> Operation

Get the inverse of an operation (what to do to undo it).

pub fn undo_count(&self) -> usize

Number of undo steps available.

pub fn redo_count(&self) -> usize

Number of redo steps available.

pub fn clear(&mut self)

Clear all history.

pub fn begin_batch(&mut self, description: &str) -> BatchBuilder<'_>

Begin a batch operation. Returns a BatchBuilder.

pub fn to_bytes(&self) -> Vec<u8>

Serialize journal to bytes (for persistence).

Binary format:

• 4 bytes: magic JRNL
• 4 bytes: version (1) as little-endian u32
• 4 bytes: number of undo entries (LE u32)
• For each entry: serialized Operation
• 4 bytes: number of redo entries (LE u32)
• For each entry: serialized Operation

pub fn from_bytes(data: &[u8]) -> Option<Self>

Deserialize journal from bytes.

Trait Implementations

impl Debug for Journal

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

Formats the value using the given formatter.

impl Default for Journal

fn default() -> Self

Returns the “default value” for a type.