Trait rustc_ap_rustc_data_structures::undo_log::UndoLogs

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

    fn in_snapshot(&self) -> bool { ... }
    fn extend<I>(&mut self, undos: I)
    where
        I: IntoIterator<Item = T>,
    { ... }
}

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

fn num_open_snapshots(&self) -> usize

How many open snapshots this undo log currently has

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.

fn clear(&mut self)

Removes all items from the undo log.

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Provided methods

fn in_snapshot(&self) -> bool

True if a snapshot has started, false otherwise

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

Extends the undo log with many undos.

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Implementations on Foreign Types

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

pub fn in_snapshot(&self) -> bool

pub fn num_open_snapshots(&self) -> usize

pub fn push(&mut self, undo: T)

pub fn clear(&mut self)

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

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Implementors

impl<T> UndoLogs<T> for NoUndo

pub fn num_open_snapshots(&self) -> usize

pub fn push(&mut self, _undo: T)

pub fn clear(&mut self)

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

pub fn num_open_snapshots(&self) -> usize

pub fn push(&mut self, undo: T)

pub fn clear(&mut self)

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