Trait rustc_data_structures::undo_log::Snapshots

source · 
pub trait Snapshots<T>: UndoLogs<T> {
    type Snapshot;

    fn actions_since_snapshot(&self, snapshot: &Self::Snapshot) -> &[T]ⓘNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8];
    fn start_snapshot(&mut self) -> Self::Snapshot;
    fn rollback_to<R>(
        &mut self,
        storage: impl FnOnce() -> R,
        snapshot: Self::Snapshot
    )
   where
        R: Rollback<T>;
    fn commit(&mut self, snapshot: Self::Snapshot);

    fn has_changes(&self, snapshot: &Self::Snapshot) -> bool { ... }
}
Expand description

A trait which extends UndoLogs to allow snapshots to be done at specific points. Each snapshot can then be used to rollback any changes to an underlying data structures if they were not desirable.

Each snapshot must be consumed linearly with either rollback_to or commit.

Required Associated Types

Required Methods

Returns the slice of actions that were taken since the snapshot began.

Starts a new snapshot. That snapshot must eventually either be committed via a call to commit or rollback via rollback_to. Snapshots can be nested (i.e., you can start a snapshot whilst another snapshot is in progress) but you must then commit or rollback the inner snapshot before attempting to commit or rollback the outer snapshot.

Rollback (undo) the changes made to storage since the snapshot.

Commit: keep the changes that have been made since the snapshot began

Provided Methods

Returns true if self has made any changes since snapshot started.

Implementors