Struct CancellationToken 

pub struct CancellationToken { /* private fields */ }

A cheap, clonable handle used to request cooperative cancellation of a run.

Cloning a token is O(1) (an Arc bump) and every clone observes the same underlying state: cancelling any clone cancels them all. Cancellation is latching — once requested it can never be undone — so a token only ever transitions from “live” to “cancelled”.

Construct a fresh, never-cancelled token with CancellationToken::new (or Default). Attach one to a run via crate::harness::context::RunContext::with_cancellation; the default RunContext carries a fresh token that is never cancelled, so cancellation is strictly opt-in.

Example

use tinyagents::harness::cancel::CancellationToken;

let token = CancellationToken::new();
assert!(!token.is_cancelled());

let clone = token.clone();
clone.cancel();
assert!(token.is_cancelled()); // visible through every clone

Implementations

impl CancellationToken

pub fn new() -> Self

Creates a fresh token that has not been cancelled.

pub fn cancel(&self)

Requests cancellation.

This latches the token into the cancelled state (it can never be undone) and wakes every task currently awaiting CancellationToken::cancelled. Calling cancel more than once is harmless and idempotent. Because every clone shares one state, this cancels the token observed through all clones.

pub fn is_cancelled(&self) -> bool

Returns true once CancellationToken::cancel has been called on this token or any of its clones.

pub async fn cancelled(&self)

Resolves as soon as the token is (or becomes) cancelled.

If the token is already cancelled the returned future completes immediately. Otherwise it parks until CancellationToken::cancel is called. The implementation registers its interest with the underlying Notify before re-checking the flag, closing the race where a cancel lands between the initial check and parking.

This future is cancel-safe and may be used in a select! arm; dropping it simply deregisters the waiter.

Trait Implementations

impl Clone for CancellationToken

fn clone(&self) -> CancellationToken

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CancellationToken

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

Formats the value using the given formatter.

impl Default for CancellationToken

A Default CancellationToken is a fresh, never-cancelled token.

fn default() -> Self

Returns the “default value” for a type.