39 lines
1.2 KiB
Rust
39 lines
1.2 KiB
Rust
use anyhow::Result;
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use wasmtime::*;
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fn main() -> Result<()> {
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// Modules can be compiled through either the text or binary format
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let engine = Engine::default();
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let wat = r#"
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(module
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(import "host" "hello" (func $host_hello (param i32)))
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(func (export "hello")
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i32.const 3
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call $host_hello)
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)
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"#;
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let module = Module::new(&engine, wat)?;
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// Create a `Linker` which will be later used to instantiate this module.
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// Host functionality is defined by name within the `Linker`.
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let mut linker = Linker::new(&engine);
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linker.func_wrap("host", "hello", |caller: Caller<'_, u32>, param: i32| {
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println!("Got {} from WebAssembly", param);
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println!("my host state is: {}", caller.data());
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})?;
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// All wasm objects operate within the context of a "store". Each
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// `Store` has a type parameter to store host-specific data, which in
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// this case we're using `4` for.
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let mut store = Store::new(&engine, 4);
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let instance = linker.instantiate(&mut store, &module)?;
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let hello = instance.get_typed_func::<(), ()>(&mut store, "hello")?;
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// And finally we can call the wasm!
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hello.call(&mut store, ())?;
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Ok(())
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}
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