Struct undo::Queue

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

A command queue wrapper.

Wraps a Record or History and gives it batch queue functionality.

Examples

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

impl Command<String> for Add {
    fn apply(&mut self, s: &mut String) -> undo::Result {
        s.push(self.0);
        Ok(())
    }

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

fn main() -> undo::Result {
    let mut record = Record::default();
    let mut queue = record.queue();
    queue.apply(Add('a'));
    queue.apply(Add('b'));
    queue.apply(Add('c'));
    assert_eq!(queue.as_receiver(), "");
    queue.commit()?;
    assert_eq!(record.as_receiver(), "abc");
    Ok(())
}

Methods

impl<'a, T, R> Queue<'a, T, R>

pub fn new(inner: &'a mut T) -> Queue<'a, T, R>

Returns a queue.

pub fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more commands in the queue.

Panics

Panics if the new capacity overflows usize.

pub fn capacity(&self) -> usize

Returns the capacity of the queue.

pub fn len(&self) -> usize

Returns the number of commands in the queue.

pub fn is_empty(&self) -> bool

Returns true if the queue is empty.

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

Queues an apply action.

pub fn undo(&mut self)

Queues an undo action.

pub fn redo(&mut self)

Queues a redo action.

pub fn cancel(self)

Cancels the queued actions.

impl<R, '_> Queue<'_, Record<R>, R>

pub fn go_to(&mut self, cursor: usize)

Queues a go_to action.

pub fn commit(self) -> Result where     R: 'static,

Applies the actions that is queued.

Errors

If an error occurs, it stops applying the actions and returns the error.

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<R, '_> Queue<'_, History<R>, R>

pub fn go_to(&mut self, branch: usize, cursor: usize)

Queues a go_to action.

pub fn commit(self) -> Result where     R: 'static,

Applies the actions that is queued.

Errors

If an error occurs, it stops applying the actions and returns the error.

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, R> From<&'a mut T> for Queue<'a, T, R>

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

Performs the conversion.

impl<T, R: 'static, C: Command<R> + 'static, '_> Extend<C> for Queue<'_, T, R>

fn extend<I: IntoIterator<Item = C>>(&mut self, commands: I)

Extends a collection with the contents of an iterator.

impl<R, '_> AsMut<R> for Queue<'_, Record<R>, R>

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

Performs the conversion.

impl<R, '_> AsMut<R> for Queue<'_, History<R>, R>

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

Performs the conversion.

impl<R, '_> AsRef<R> for Queue<'_, Record<R>, R>

fn as_ref(&self) -> &R

Performs the conversion.

impl<R, '_> AsRef<R> for Queue<'_, History<R>, R>

fn as_ref(&self) -> &R

Performs the conversion.

impl<'a, T: Debug, R: Debug> Debug for Queue<'a, T, R>

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

Formats the value using the given formatter.