Struct TaskHandle 

pub struct TaskHandle(/* private fields */);

A cloneable, shareable handle to an optional GantzTask, suitable for storage in node state or transfer along graph edges as an opaque SteelVal.

Cloning shares the underlying cell. Steel’s FromSteelVal for custom types clones, so a handle extracted from the VM still refers to the same task. The result is delivered exactly once. TaskHandle::check consumes the result on completion. When several holders share the cell, only the first holder checked after completion delivers. The rest observe None. TaskHandle::take and TaskHandle::cancel remove the task from every clone at once.

Implementations

impl TaskHandle

pub fn new(task: GantzTask) -> Self

Wrap a task in a fresh shareable handle.

pub fn take(&self) -> Option<GantzTask>

Take the task out of the handle, leaving None for every clone.

pub fn check(&self) -> Option<Result<SteelVal, String>>

Check the contained task in place, leaving it in the handle.

Returns None while pending, after the result has been delivered, or when the handle was taken or cancelled.

pub fn cancel(&self) -> bool

Drop the contained task, cancelling it for every clone.

Returns whether a task was present to cancel.

Trait Implementations

impl Clone for TaskHandle

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Custom for TaskHandle

fn fmt(&self) -> Option<Result<String, Error>>

fn into_serializable_steelval(&mut self) -> Option<SerializableSteelVal>

fn as_iterator(&self) -> Option<Box<dyn Iterator<Item = SteelVal>>>

fn gc_drop_mut(&mut self, _drop_handler: &mut IterativeDropHandler<'_>)

fn gc_visit_children(&self, _context: &mut MarkAndSweepContext<'_>)

fn visit_equality(&self, _visitor: &mut EqualityVisitor<'_>)

fn equality_hint(&self, _other: &dyn CustomType) -> bool

fn equality_hint_general(&self, _other: &SteelVal) -> bool