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
35 lines
1.3 KiB
Rust
35 lines
1.3 KiB
Rust
//! Example of limiting a WebAssembly function's runtime using "fuel consumption".
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// You can execute this example with `cargo run --example fuel`
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use anyhow::Result;
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use wasmtime::*;
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fn main() -> Result<()> {
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let mut config = Config::new();
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config.consume_fuel(true);
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let engine = Engine::new(&config)?;
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let mut store = Store::new(&engine, ());
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store.add_fuel(10_000)?;
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let module = Module::from_file(store.engine(), "examples/fuel.wat")?;
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let instance = Instance::new(&mut store, &module, &[])?;
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// Invoke `fibonacci` export with higher and higher numbers until we exhaust our fuel.
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let fibonacci = instance.get_typed_func::<i32, i32>(&mut store, "fibonacci")?;
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for n in 1.. {
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let fuel_before = store.fuel_consumed().unwrap();
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let output = match fibonacci.call(&mut store, n) {
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Ok(v) => v,
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Err(e) => {
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assert_eq!(e.downcast::<Trap>()?, Trap::OutOfFuel);
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println!("Exhausted fuel computing fib({})", n);
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break;
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}
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};
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let fuel_consumed = store.fuel_consumed().unwrap() - fuel_before;
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println!("fib({}) = {} [consumed {} fuel]", n, output, fuel_consumed);
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store.add_fuel(fuel_consumed)?;
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}
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Ok(())
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}
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