Struct undo::Checkpoint

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

A checkpoint wrapper.

Wraps a Record or History and gives it checkpoint functionality.

Examples

#[derive(Debug)]
struct Add(char);

impl Command<String> for Add {
    fn apply(&mut self, s: &mut String) -> Result<(), Box<dyn Error + Send + Sync>> {
        s.push(self.0);
        Ok(())
    }

    fn undo(&mut self, s: &mut String) -> Result<(), Box<dyn Error + Send + Sync>> {
        self.0 = s.pop().ok_or("`s` is empty")?;
        Ok(())
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    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.as_receiver(), "abc");
        cp.cancel()?;
    }
    assert_eq!(record.as_receiver(), "");
    Ok(())
}

Methods

impl<'a, R> Checkpoint<'a, Record<R>, R>

pub fn apply(     &mut self,     command: impl Command<R> + 'static ) -> Result<(), Error<R>> where     R: 'static,

Calls the apply method.

pub fn undo(&mut self) -> Option<Result<(), Error<R>>>

Calls the undo method.

pub fn redo(&mut self) -> Option<Result<(), Error<R>>>

Calls the redo method.

pub fn go_to(&mut self, cursor: usize) -> Option<Result<(), Error<R>>>

Calls the go_to method.

pub fn commit(self)

Commits the changes and consumes the checkpoint.

pub fn cancel(self) -> Result<(), Error<R>>

Cancels the changes and consumes the checkpoint.

Errors

If an error occur when canceling the changes, the error is returned together with the command.

pub fn checkpoint(&mut self) -> Checkpoint<Record<R>, R>

Returns a checkpoint.

pub fn queue(&mut self) -> Queue<Record<R>, R>

Returns a queue.

pub fn as_receiver(&self) -> &R

Returns a reference to the receiver.

pub fn as_mut_receiver(&mut self) -> &mut R

Returns a mutable reference to the receiver.

This method should only be used when doing changes that should not be able to be undone.

impl<'a, R> Checkpoint<'a, History<R>, R>

pub fn apply(     &mut self,     command: impl Command<R> + 'static ) -> Result<(), Error<R>> where     R: 'static,

Calls the apply method.

pub fn undo(&mut self) -> Option<Result<(), Error<R>>>

Calls the undo method.

pub fn redo(&mut self) -> Option<Result<(), Error<R>>>

Calls the redo method.

pub fn go_to(     &mut self,     branch: usize,     cursor: usize ) -> Option<Result<(), Error<R>>> where     R: 'static,

Calls the go_to method.

pub fn commit(self)

Commits the changes and consumes the checkpoint.

pub fn cancel(self) -> Result<(), Error<R>> where     R: 'static,

Cancels the changes and consumes the checkpoint.

Errors

If an error occur when canceling the changes, the error is returned together with the command.

pub fn checkpoint(&mut self) -> Checkpoint<History<R>, R>

Returns a checkpoint.

pub fn queue(&mut self) -> Queue<History<R>, R>

Returns a queue.

pub fn as_receiver(&self) -> &R

Returns a reference to the receiver.

pub fn as_mut_receiver(&mut self) -> &mut R

Returns a mutable reference to the receiver.

This method should only be used when doing changes that should not be able to be undone.

Trait Implementations

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

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

Formats the value using the given formatter.

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

fn from(inner: &'a mut T) -> Self

Performs the conversion.

impl<'a, R> AsRef<R> for Checkpoint<'a, Record<R>, R>

fn as_ref(&self) -> &R

Performs the conversion.

impl<'a, R> AsMut<R> for Checkpoint<'a, Record<R>, R>

fn as_mut(&mut self) -> &mut R

Performs the conversion.

impl<'a, R> AsRef<R> for Checkpoint<'a, History<R>, R>

fn as_ref(&self) -> &R

Performs the conversion.

impl<'a, R> AsMut<R> for Checkpoint<'a, History<R>, R>

fn as_mut(&mut self) -> &mut R

Performs the conversion.