Struct undo::Checkpoint

pub struct Checkpoint<'a, T: 'static> { /* fields omitted */ }

A checkpoint wrapper.

Wraps a record or history and gives it checkpoint functionality. This allows the record or history to cancel all changes made since creating the checkpoint.

Examples

let mut record = Record::default();
let mut cp = record.checkpoint();
cp.apply(Add('a'))?;
cp.apply(Add('b'))?;
cp.apply(Add('c'))?;
assert_eq!(cp.target(), "abc");
cp.cancel()?;
assert_eq!(record.target(), "");

Implementations

impl<T, '_> Checkpoint<'_, T>

pub fn apply(&mut self, command: impl Command<T>) -> Result

Calls the apply method.

pub fn undo(&mut self) -> Result

Calls the undo method.

pub fn redo(&mut self) -> Result

Calls the redo method.

pub fn commit(self)

Commits the changes and consumes the checkpoint.

pub fn cancel(self) -> Result

Cancels the changes and consumes the checkpoint.

Errors

If an error occur when canceling the changes, the error is returned and the remaining commands are not canceled.

pub fn queue(&mut self) -> Queue<'_, T>

Returns a queue.

pub fn checkpoint(&mut self) -> Checkpoint<'_, T>

Returns a checkpoint.

pub fn target(&self) -> &T

Returns a reference to the target.

Trait Implementations

impl<'a, T: Debug + 'static> Debug for Checkpoint<'a, T>

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

Formats the value using the given formatter.

impl<'a, T> From<&'a mut Record<T>> for Checkpoint<'a, T>

fn from(record: &'a mut Record<T>) -> Self

Performs the conversion.