Struct CancellationToken 

pub struct CancellationToken { /* private fields */ }

Token for checking, waiting on, and triggering cancellation.

Example

// Create a token
let token = CancellationToken::new();

// Clone to pass to other threads/tasks
let token2 = token.clone();

// Check if cancelled (fast, lock-free)
if token.is_cancelled() {
    return Err("operation cancelled");
}

// Trigger cancellation
token.cancel();

// Block until cancelled (sync)
token.wait();

// Wait with timeout
if !token.wait_timeout(Duration::from_secs(5)) {
    println!("timed out waiting for cancellation");
}

// Await cancellation (async)
token.cancelled().await;

Implementations

impl CancellationToken

pub fn new() -> Self

Create a new cancellation token.

pub fn new_with_timeout(timeout: Duration) -> Self

Create a new cancellation token with automatic timeout.

Important: The timeout does NOT start immediately. It only starts when the token is passed to a runtime function (call_function, etc.). This allows you to create the token ahead of time without the clock ticking.

pub fn is_cancelled(&self) -> bool

Check if cancelled.

This is a lock-free atomic read, extremely fast for polling.

pub fn cancel(&self)

Trigger cancellation.

Safe to call multiple times - only the first call has effect. All waiters (sync and async) will be notified.

pub fn wait(&self)

Block the current thread until cancellation occurs.

If already cancelled, returns immediately.

pub fn wait_timeout(&self, timeout: Duration) -> bool

Block until cancelled or timeout expires.

Returns true if cancelled, false if the timeout elapsed first.

pub async fn cancelled(&self)

Await cancellation asynchronously.

If already cancelled, returns immediately.

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

fn default() -> Self

Returns the “default value” for a type.