Struct Cx 

pub struct Cx { /* private fields */ }

Capability context handle.

Cheaply cloneable. Check is_cancelled() at natural yield points (loop iterations, before I/O, before expensive computation).

Implementations

impl Cx

pub fn background() -> (Self, CxController)

Create a root context with no deadline.

pub fn with_deadline(deadline: Duration) -> (Self, CxController)

Create a root context with a deadline.

pub fn lab(clock: &LabClock) -> (Self, CxController)

Create a root context using a LabClock for deterministic testing.

pub fn lab_with_deadline( clock: &LabClock, deadline: Duration, ) -> (Self, CxController)

Create a lab context with a deadline.

pub fn child(&self, deadline: Duration) -> (Self, CxController)

Derive a child context with a tighter deadline.

The effective deadline is min(parent.deadline(), child_deadline). Cancelling the parent also cancels the child (checked via chain walk).

pub fn child_inherit(&self) -> (Self, CxController)

Derive a child context that inherits the parent deadline.

pub fn id(&self) -> u64

Unique identifier for this context (for tracing/logging).

pub fn is_cancelled(&self) -> bool

Check if this context (or any ancestor) has been cancelled.

pub fn is_expired(&self) -> bool

Check if the deadline has passed.

pub fn is_done(&self) -> bool

Check if the context is done (cancelled or expired).

pub fn deadline(&self) -> Option<Duration>

Return the effective deadline as a Duration from context creation, considering the full parent chain. Returns None if no deadline is set.

pub fn remaining(&self) -> Option<Duration>

Remaining time until deadline (saturates to zero, never negative). Returns None if no deadline is set.

pub fn remaining_us(&self) -> Option<u64>

Remaining time in microseconds, or None if no deadline.

pub fn now(&self) -> Instant

Current time according to this context’s time source.

pub fn is_lab(&self) -> bool

Whether this context uses a lab clock.

pub fn sleep(&self, duration: Duration) -> bool

Sleep for the given duration, respecting cancellation and deadline.

Returns true if the full duration elapsed, false if cancelled or deadline expired early.

impl Cx

pub fn check(&self) -> Result<(), CxError>

Check if the context is still live; return Err if cancelled or expired.

Intended for use at yield points:

cx.check()?;
// ... continue work ...

Trait Implementations

impl Clone for Cx

fn clone(&self) -> Cx

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Cx

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

Formats the value using the given formatter.