b0939f6626
* Remove explicit `S` type parameters This commit removes the explicit `S` type parameter on `Func::typed` and `Instance::get_typed_func`. Historical versions of Rust required that this be a type parameter but recent rustcs support a mixture of explicit type parameters and `impl Trait`. This removes, at callsites, a superfluous `, _` argument which otherwise never needs specification. * Fix mdbook examples
49 lines
1.8 KiB
Rust
49 lines
1.8 KiB
Rust
//! Example of interrupting a WebAssembly function's runtime via epoch
|
|
//! changes ("epoch interruption") in a synchronous context. To see
|
|
//! an example of setup for asynchronous usage, see
|
|
//! `tests/all/epoch_interruption.rs`
|
|
|
|
use anyhow::Error;
|
|
use std::sync::Arc;
|
|
use wasmtime::{Config, Engine, Instance, Module, Store};
|
|
|
|
fn main() -> Result<(), Error> {
|
|
// Set up an engine configured with epoch interruption enabled.
|
|
let mut config = Config::new();
|
|
config.epoch_interruption(true);
|
|
let engine = Arc::new(Engine::new(&config)?);
|
|
|
|
let mut store = Store::new(&engine, ());
|
|
// Configure the store to trap on reaching the epoch deadline.
|
|
// This is the default, but we do it explicitly here to
|
|
// demonstrate.
|
|
store.epoch_deadline_trap();
|
|
// Configure the store to have an initial epoch deadline one tick
|
|
// in the future.
|
|
store.set_epoch_deadline(1);
|
|
|
|
// Reuse the fibonacci function from the Fuel example. This is a
|
|
// long-running function that we will want to interrupt.
|
|
let module = Module::from_file(store.engine(), "examples/fuel.wat")?;
|
|
let instance = Instance::new(&mut store, &module, &[])?;
|
|
|
|
// Start a thread that will bump the epoch after 1 second.
|
|
let engine_clone = engine.clone();
|
|
std::thread::spawn(move || {
|
|
std::thread::sleep(std::time::Duration::from_secs(1));
|
|
engine_clone.increment_epoch();
|
|
});
|
|
|
|
// Invoke `fibonacci` with a large argument such that a normal
|
|
// invocation would take many seconds to complete.
|
|
let fibonacci = instance.get_typed_func::<i32, i32>(&mut store, "fibonacci")?;
|
|
match fibonacci.call(&mut store, 100) {
|
|
Ok(_) => panic!("Somehow we computed recursive fib(100) in less than a second!"),
|
|
Err(_) => {
|
|
println!("Trapped out of fib(100) after epoch increment");
|
|
}
|
|
};
|
|
|
|
Ok(())
|
|
}
|