/
handle.rs
49 lines (44 loc) · 1.52 KB
/
handle.rs
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use crate::runtime::context;
use crate::time::driver::Inner;
use std::fmt;
use std::sync::{Arc, Weak};
/// Handle to time driver instance.
#[derive(Clone)]
pub(crate) struct Handle {
inner: Weak<Inner>,
}
impl Handle {
/// Creates a new timer `Handle` from a shared `Inner` timer state.
pub(crate) fn new(inner: Weak<Inner>) -> Self {
Handle { inner }
}
/// Tries to get a handle to the current timer.
///
/// # Panics
///
/// This function panics if there is no current timer set.
///
/// It can be triggered when `Builder::enable_time()` or
/// `Builder::enable_all()` are not included in the builder.
///
/// It can also panic whenever a timer is created outside of a Tokio
/// runtime. That is why `rt.block_on(sleep(...))` will panic,
/// since the function is executed outside of the runtime.
/// Whereas `rt.block_on(async {sleep(...).await})` doesn't
/// panic. And this is because wrapping the function on an async makes it
/// lazy, and so gets executed inside the runtime successfuly without
/// panicking.
pub(crate) fn current() -> Self {
context::time_handle()
.expect("there is no timer running, must be called from the context of Tokio runtime")
}
/// Tries to return a strong ref to the inner
pub(crate) fn inner(&self) -> Option<Arc<Inner>> {
self.inner.upgrade()
}
}
impl fmt::Debug for Handle {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Handle")
}
}