Struct GuardCondition

pub struct GuardCondition { /* private fields */ }

A waitable entity used for waking up a wait set manually.

If a wait set that is currently waiting on events should be interrupted from a separate thread, this can be done by adding an Arc<GuardCondition> to the wait set, and calling trigger() on the same GuardCondition while the wait set is waiting.

The guard condition may be reused multiple times, but like other waitable entities, can not be used in multiple wait sets concurrently.

Example

let context = Context::default();

let atomic_bool = Arc::new(std::sync::atomic::AtomicBool::new(false));
let atomic_bool_for_closure = Arc::clone(&atomic_bool);

let gc = Arc::new(GuardCondition::new_with_callback(
    &context,
    move || {
        atomic_bool_for_closure.store(true, Ordering::Relaxed);
    },
));

let mut ws = WaitSet::new(0, 1, 0, 0, 0, 0, &context)?;
ws.add_guard_condition(Arc::clone(&gc))?;

// Trigger the guard condition, firing the callback and waking the wait set being waited on, if any.
gc.trigger()?;

// The provided callback has now been called.
assert_eq!(atomic_bool.load(Ordering::Relaxed), true);

// The wait call will now immediately return.
ws.wait(Some(std::time::Duration::from_millis(10)))?;

Implementations

impl GuardCondition

pub fn new(context: &Context) -> Self

Creates a new guard condition with no callback.

pub fn new_with_callback<F>(context: &Context, callback: F) -> Self

where F: Fn() + Send + Sync + 'static,

Creates a new guard condition with a callback.

pub fn trigger(&self) -> Result<(), RclrsError>

Triggers this guard condition, activating the wait set, and calling the optionally assigned callback.

Trait Implementations

impl Drop for GuardCondition

fn drop(&mut self)

Executes the destructor for this type.

impl PartialEq for GuardCondition

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for GuardCondition