pub trait UndoLogs<T> {
    // Required methods
    fn num_open_snapshots(&self) -> usize;
    fn push(&mut self, undo: T);
    fn clear(&mut self);

    // Provided methods
    fn in_snapshot(&self) -> bool { ... }
    fn extend<I>(&mut self, undos: I)
       where Self: Sized,
             I: IntoIterator<Item = T> { ... }
}
Expand description

A trait which allows undo actions (T) to be pushed which can be used to rollback actio at a later time if needed.

The undo actions themselves are opaque to UndoLogs, only specified Rollback implementations need to know what an action is and how to reverse it.

Required Methods§

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fn num_open_snapshots(&self) -> usize

How many open snapshots this undo log currently has

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fn push(&mut self, undo: T)

Pushes a new “undo item” onto the undo log. This method is invoked when some action is taken (e.g., a variable is unified). It records the info needed to reverse that action should an enclosing snapshot be rolleod back.

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fn clear(&mut self)

Removes all items from the undo log.

Provided Methods§

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fn in_snapshot(&self) -> bool

True if a snapshot has started, false otherwise

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fn extend<I>(&mut self, undos: I)
where Self: Sized, I: IntoIterator<Item = T>,

Extends the undo log with many undos.

Implementations on Foreign Types§

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impl<'a, T, U> UndoLogs<T> for &'a mut U
where U: UndoLogs<T>,

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fn in_snapshot(&self) -> bool

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fn num_open_snapshots(&self) -> usize

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fn push(&mut self, undo: T)

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fn clear(&mut self)

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fn extend<I>(&mut self, undos: I)
where &'a mut U: Sized, I: IntoIterator<Item = T>,

Implementors§

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impl<T> UndoLogs<T> for NoUndo

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impl<T> UndoLogs<T> for VecLog<T>