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74 lines
2.4 KiB
74 lines
2.4 KiB
//! Example of instantiating a wasm module which uses WASI preview1 imports
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//! implemented through the async preview2 WASI implementation.
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/*
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You can execute this example with:
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cmake examples/
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cargo run --example wasi-async
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*/
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use anyhow::Result;
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use wasmtime::{Config, Engine, Linker, Module, Store};
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struct WasiHostCtx {
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preview2_ctx: wasmtime_wasi::WasiCtx,
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preview2_table: wasmtime::component::ResourceTable,
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preview1_adapter: wasmtime_wasi::preview1::WasiPreview1Adapter,
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}
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impl wasmtime_wasi::WasiView for WasiHostCtx {
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fn table(&mut self) -> &mut wasmtime::component::ResourceTable {
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&mut self.preview2_table
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}
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fn ctx(&mut self) -> &mut wasmtime_wasi::WasiCtx {
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&mut self.preview2_ctx
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}
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}
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impl wasmtime_wasi::preview1::WasiPreview1View for WasiHostCtx {
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fn adapter(&self) -> &wasmtime_wasi::preview1::WasiPreview1Adapter {
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&self.preview1_adapter
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}
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fn adapter_mut(&mut self) -> &mut wasmtime_wasi::preview1::WasiPreview1Adapter {
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&mut self.preview1_adapter
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}
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}
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#[tokio::main]
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async fn main() -> Result<()> {
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// Construct the wasm engine with async support enabled.
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let mut config = Config::new();
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config.async_support(true);
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let engine = Engine::new(&config)?;
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// Add the WASI preview1 API to the linker (will be implemented in terms of
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// the preview2 API)
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let mut linker: Linker<WasiHostCtx> = Linker::new(&engine);
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wasmtime_wasi::preview1::add_to_linker_async(&mut linker, |t| t)?;
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// Add capabilities (e.g. filesystem access) to the WASI preview2 context here.
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let wasi_ctx = wasmtime_wasi::WasiCtxBuilder::new().inherit_stdio().build();
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let host_ctx = WasiHostCtx {
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preview2_ctx: wasi_ctx,
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preview2_table: wasmtime::component::ResourceTable::new(),
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preview1_adapter: wasmtime_wasi::preview1::WasiPreview1Adapter::new(),
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};
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let mut store: Store<WasiHostCtx> = Store::new(&engine, host_ctx);
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// Instantiate our 'Hello World' wasm module.
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// Note: This is a module built against the preview1 WASI API.
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let module = Module::from_file(&engine, "target/wasm32-wasi/debug/wasi.wasm")?;
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let func = linker
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.module_async(&mut store, "", &module)
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.await?
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.get_default(&mut store, "")?
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.typed::<(), ()>(&store)?;
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// Invoke the WASI program default function.
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func.call_async(&mut store, ()).await?;
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Ok(())
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}
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