6571fb8f4f
* Remove `HostRef` from the `wasmtime` public API
This commit removes all remaining usages of `HostRef` in the public API
of the `wasmtime` crate. This involved a number of API decisions such
as:
* None of `Func`, `Global`, `Table`, or `Memory` are wrapped in `HostRef`
* All of `Func`, `Global`, `Table`, and `Memory` implement `Clone` now.
* Methods called `type` are renamed to `ty` to avoid typing `r#type`.
* Methods requiring mutability for external items now no longer require
mutability. The mutable reference here is sort of a lie anyway since
the internals are aliased by the underlying module anyway. This
affects:
* `Table::set`
* `Table::grow`
* `Memory::grow`
* `Instance::set_signal_handler`
* The `Val::FuncRef` type is now no longer automatically coerced to
`AnyRef`. This is technically a breaking change which is pretty bad,
but I'm hoping that we can live with this interim state while we sort
out the `AnyRef` story in general.
* The implementation of the C API was refactored and updated in a few
locations to account for these changes:
* Accessing the exports of an instance are now cached to ensure we
always hand out the same `HostRef` values.
* `wasm_*_t` for external values no longer have internal cache,
instead they all wrap `wasm_external_t` and have an unchecked
accessor for the underlying variant (since the type is proof that
it's there). This makes casting back and forth much more trivial.
This is all related to #708 and while there's still more work to be done
in terms of documentation, this is the major bulk of the rest of the
implementation work on #708 I believe.
* More API updates
* Run rustfmt
* Fix a doc test
* More test updates
67 lines
2.4 KiB
Rust
67 lines
2.4 KiB
Rust
//! Translation of hello example
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use anyhow::{ensure, Context as _, Result};
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use std::rc::Rc;
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use wasmtime::*;
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struct HelloCallback;
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impl Callable for HelloCallback {
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fn call(&self, _params: &[Val], _results: &mut [Val]) -> Result<(), Trap> {
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println!("Calling back...");
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println!("> Hello World!");
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Ok(())
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}
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}
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fn main() -> Result<()> {
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// Configure the initial compilation environment, creating the global
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// `Store` structure. Note that you can also tweak configuration settings
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// with a `Config` and an `Engine` if desired.
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println!("Initializing...");
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let store = Store::default();
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// Next upload the `*.wasm` binary file, which in this case we're going to
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// be parsing an inline text format into a binary.
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println!("Loading binary...");
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let binary = wat::parse_str(
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r#"
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(module
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(func $hello (import "" "hello"))
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(func (export "run") (call $hello))
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)
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"#,
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)?;
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// Compiler the `*.wasm` binary into an in-memory instance of a `Module`.
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println!("Compiling module...");
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let module = Module::new(&store, &binary).context("> Error compiling module!")?;
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// Here we handle the imports of the module, which in this case is our
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// `HelloCallback` type and its associated implementation of `Callback.
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println!("Creating callback...");
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let hello_type = FuncType::new(Box::new([]), Box::new([]));
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let hello_func = Func::new(&store, hello_type, Rc::new(HelloCallback));
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// Once we've got that all set up we can then move to the instantiation
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// phase, pairing together a compiled module as well as a set of imports.
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// Note that this is where the wasm `start` function, if any, would run.
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println!("Instantiating module...");
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let imports = vec![hello_func.into()];
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let instance =
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Instance::new(&store, &module, &imports).context("> Error instantiating module!")?;
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// Next we poke around a bit to extract the `run` function from the module.
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println!("Extracting export...");
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let exports = instance.exports();
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ensure!(!exports.is_empty(), "> Error accessing exports!");
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let run_func = exports[0].func().context("> Error accessing exports!")?;
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// And last but not least we can call it!
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println!("Calling export...");
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run_func.call(&[])?;
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println!("Done.");
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Ok(())
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}
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