e245e6dd9c
* Add examples of linking and WASI This commit adds two example programs, one for linking two modules together and one for instantiating WASI. The linkage example additionally uses WASI to get some meaningful output at this time. cc #1272 * Add examples to the book as well * More links! * Ignore examples from rustdoc testsing * More example updates * More ignored
44 lines
1.4 KiB
Rust
44 lines
1.4 KiB
Rust
//! Example of instantiating of instantiating a wasm module which uses WASI
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//! imports.
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// You can execute this example with `cargo run --example wasi`
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use anyhow::Result;
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use wasmtime::*;
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use wasmtime_wasi::{Wasi, WasiCtx};
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fn main() -> Result<()> {
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let store = Store::default();
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let module = Module::from_file(&store, "target/wasm32-wasi/debug/wasi.wasm")?;
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// Create an instance of `Wasi` which contains a `WasiCtx`. Note that
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// `WasiCtx` provides a number of ways to configure what the target program
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// will have access to.
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let wasi = Wasi::new(&store, WasiCtx::new(std::env::args())?);
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let mut imports = Vec::new();
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for import in module.imports() {
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if import.module() == "wasi_snapshot_preview1" {
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if let Some(export) = wasi.get_export(import.name()) {
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imports.push(Extern::from(export.clone()));
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continue;
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}
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}
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panic!(
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"couldn't find import for `{}::{}`",
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import.module(),
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import.name()
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);
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}
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// Instance our module with the imports we've created, then we can run the
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// standard wasi `_start` function.
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let instance = Instance::new(&module, &imports)?;
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let start = instance
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.get_export("_start")
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.and_then(|e| e.func())
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.unwrap();
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let start = start.get0::<()>()?;
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start()?;
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Ok(())
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}
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