Enum wasmtime_wasi::preview2::HostPollable

pub enum HostPollable {
    TableEntry {
        index: u32,
        make_future: MakeFuture,
    },
    Closure(ClosureFuture),
}

A host representation of the wasi:poll/poll.pollable resource.

A pollable is not the same thing as a Rust Future: the same pollable may be used to repeatedly check for readiness of a given condition, e.g. if a stream is readable or writable. So, rather than containing a Future, which can only become Ready once, a HostPollable contains a way to create a Future in each call to poll_oneoff.

Variants

TableEntry

Fields

index: u32

make_future: MakeFuture

Create a Future by calling a fn on another resource in the table. This indirection means the created Future can use a mut borrow of another resource in the Table (e.g. a stream)

Closure(ClosureFuture)

Create a future by calling an owned, static closure. This is used for pollables which do not share state with another resource in the Table (e.g. a timer)