Module runtime

This module provides an “ambient Tokio runtime” with_ambient_tokio_runtime. Embedders of wasmtime-wasi may do so from synchronous Rust, and not use tokio directly. The implementation of wasmtime-wasi requires a tokio executor in a way that is deeply tied to its design. When used from a sychrnonous wasmtime context, this module provides the wrapper function in_tokio used throughout the shim implementations of synchronous component binding Host traits in terms of the async ones.

This module also provides a thin wrapper on tokio’s tasks. AbortOnDropJoinHandle, which is exactly like a [tokio::task::JoinHandle] except for the obvious behavioral change. This whole crate, and any child crates which spawn tasks as part of their implementations, should please use this crate’s spawn and spawn_blocking over tokio’s. so we wanted the type name to stick out if someone misses it.

Each of these facilities should be used by dependencies of wasmtime-wasi which when implementing component bindings.

Structs

• AbortOnDropJoinHandle
  Exactly like a [tokio::task::JoinHandle], except that it aborts the task when the handle is dropped.

Functions

• in_tokio
• poll_noop
  Attempts to get the result of a future.
• spawn
• spawn_blocking
• with_ambient_tokio_runtime
  Executes the closure f with an “ambient Tokio runtime” which basically means that if code in f tries to get a runtime Handle it’ll succeed.