Enum RollbackProbe 

pub enum RollbackProbe {
    Proven,
    NotApplicable,
}

The outcome of OncePtrCell::dbg_rollback_reenterable — exactly the two answers that probe can give, and no third one it could never produce.

In particular there is no “rollback is broken” variant: the probe cannot distinguish that from “another thread legitimately owns the cell now”, because both make its postcondition CAS fail identically. See the method’s own docs for the full argument.

Variants

Proven

The rollback provably cleared the sentinel: the probe’s postcondition CAS re-won the cell afterwards, so no future winner or spinning loser can be wedged by it. The cell is restored to UNINIT before returning.

NotApplicable

The probe could not run its check, and this is NOT evidence that rollback is broken. Either the cell was not UNINIT when the probe entered (already READY, or owned by another thread at that instant) — in which case the probe never touched it at all — or a real get_or_try_init caller re-won the cell during the probe’s own rollback-then-reCAS window, in which case the probe still does not touch it, but the cell is no longer necessarily UNINIT: the real caller may already be running init, or may have published READY, by the time this returns. Either way the probe never clobbers a state it does not own.

Trait Implementations

impl Clone for RollbackProbe

fn clone(&self) -> RollbackProbe

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RollbackProbe

impl Debug for RollbackProbe

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

Formats the value using the given formatter.

impl Eq for RollbackProbe

impl PartialEq for RollbackProbe

fn eq(&self, other: &RollbackProbe) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for RollbackProbe