9364eb1d98
* Compute instance exports on demand. Instead having instances eagerly compute a Vec of Externs, and bumping the refcount for each Extern, compute Externs on demand. This also enables `Instance::get_export` to avoid doing a linear search. This also means that the closure returned by `get0` and friends now holds an `InstanceHandle` to dynamically hold the instance live rather than being scoped to a lifetime. * Compute module imports and exports on demand too. And compute Extern::ty on demand too. * Add a utility function for computing an ExternType. * Add a utility function for looking up a function's signature. * Add a utility function for computing the ValType of a Global. * Rename wasmtime_environ::Export to EntityIndex. This helps differentiate it from other Export types in the tree, and describes what it is. * Fix a typo in a comment. * Simplify module imports and exports. * Make `Instance::exports` return the export names. This significantly simplifies the public API, as it's relatively common to need the names, and this avoids the need to do a zip with `Module::exports`. This also changes `ImportType` and `ExportType` to have public members instead of private members and accessors, as I find that simplifies the usage particularly in cases where there are temporary instances. * Remove `Instance::module`. This doesn't quite remove `Instance`'s `module` member, it gets a step closer. * Use a InstanceHandle utility function. * Don't consume self in the `Func::get*` methods. Instead, just create a closure containing the instance handle and the export for them to call. * Use `ExactSizeIterator` to avoid needing separate `num_*` methods. * Rename `Extern::func()` etc. to `into_func()` etc. * Revise examples to avoid using `nth`. * Add convenience methods to instance for getting specific extern types. * Use the convenience functions in more tests and examples. * Avoid cloning strings for `ImportType` and `ExportType`. * Remove more obviated clone() calls. * Simplify `Func`'s closure state. * Make wasmtime::Export's fields private. This makes them more consistent with ExportType. * Fix compilation error. * Make a lifetime parameter explicit, and use better lifetime names. Instead of 'me, use 'instance and 'module to make it clear what the lifetime is. * More lifetime cleanups.
41 lines
1.3 KiB
Rust
41 lines
1.3 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.get_func("_start").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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