pub trait Pollable: Send + 'static {
// Required method
fn ready<'life0, 'async_trait>(
&'life0 mut self,
) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>
where 'life0: 'async_trait,
Self: 'async_trait;
}Expand description
The trait used to implement DynPollable to create a pollable
resource in wasi:io/poll.
This trait is the internal implementation detail of any pollable resource in
this crate’s implementation of WASI. The ready function is an async fn
which resolves when the implementation is ready. Using native async Rust
enables this type’s readiness to compose with other types’ readiness
throughout the WASI implementation.
This trait is used in conjunction with subscribe to create a pollable
resource.
§Example
This is a simple example of creating a Pollable resource from a few
parameters.
Instant) {} } }
use tokio::time::{self, Duration, Instant};
use wasmtime_wasi_io::{IoView, poll::{Pollable, subscribe, DynPollable}, async_trait};
use wasmtime::component::Resource;
use wasmtime::Result;
fn sleep(cx: &mut dyn IoView, dur: Duration) -> Result<Resource<DynPollable>> {
let end = Instant::now() + dur;
let sleep = MySleep { end };
let sleep_resource = cx.table().push(sleep)?;
subscribe(cx.table(), sleep_resource)
}
struct MySleep {
end: Instant,
}
#[async_trait]
impl Pollable for MySleep {
async fn ready(&mut self) {
tokio::time::sleep_until(self.end).await;
}
}Required Methods§
Sourcefn ready<'life0, 'async_trait>(
&'life0 mut self,
) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>where
'life0: 'async_trait,
Self: 'async_trait,
fn ready<'life0, 'async_trait>(
&'life0 mut self,
) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>where
'life0: 'async_trait,
Self: 'async_trait,
An asynchronous function which resolves when this object’s readiness operation is ready.
This function is invoked as part of poll in wasi:io/poll. The
meaning of when this function Returns depends on what object this
Pollable is attached to. When the returned future resolves then the
corresponding call to wasi:io/poll will return.
Note that this method does not return an error. Returning an error
should be done through accessors on the object that this pollable is
connected to. The call to wasi:io/poll itself does not return errors,
only a list of ready objects.