Files
wasmtime/crates/api/tests/import_calling_export.rs
Alex Crichton 16804673a2 Support parsing the text format in wasmtime crate (#813)
* Support parsing the text format in `wasmtime` crate

This commit adds support to the `wasmtime::Module` type to parse the
text format. This is often quite convenient to support in testing or
tinkering with the runtime. Additionally the `wat` parser is pretty
lightweight and easy to add to builds, so it's relatively easy for us to
support as well!

The exact manner that this is now supported comes with a few updates to
the existing API:

* A new optional feature of the `wasmtime` crate, `wat`, has been added.
  This is enabled by default.
* The `Module::new` API now takes `impl AsRef<[u8]>` instead of just
  `&[u8]`, and when the `wat` feature is enabled it will attempt to
  interpret it either as a wasm binary or as the text format. Note that
  this check is quite cheap since you just check the first byte.
* A `Module::from_file` API was added as a convenience to parse a file
  from disk, allowing error messages for `*.wat` files on disk to be a
  bit nicer.
* APIs like `Module::new_unchecked` and `Module::validate` remain
  unchanged, they require the binary format to be called.

The intention here is to make this as convenient as possible for new
developers of the `wasmtime` crate. By changing the default behavior
though this has ramifications such as, for example, supporting the text
format implicitly through the C API now.

* Handle review comments

* Update more tests to avoid usage of `wat` crate

* Go back to unchecked for now in wasm_module_new

Looks like C# tests rely on this?
2020-01-24 14:20:51 -06:00

67 lines
1.6 KiB
Rust

use std::cell::RefCell;
use std::rc::Rc;
use wasmtime::*;
#[test]
fn test_import_calling_export() {
const WAT: &str = r#"
(module
(type $t0 (func))
(import "" "imp" (func $.imp (type $t0)))
(func $run call $.imp)
(func $other)
(export "run" (func $run))
(export "other" (func $other))
)
"#;
struct Callback {
pub other: RefCell<Option<Func>>,
}
impl Callable for Callback {
fn call(&self, _params: &[Val], _results: &mut [Val]) -> Result<(), Trap> {
self.other
.borrow()
.as_ref()
.expect("expected a function ref")
.call(&[])
.expect("expected function not to trap");
Ok(())
}
}
let store = Store::default();
let module = Module::new(&store, WAT).expect("failed to create module");
let callback = Rc::new(Callback {
other: RefCell::new(None),
});
let callback_func = Func::new(
&store,
FuncType::new(Box::new([]), Box::new([])),
callback.clone(),
);
let imports = vec![callback_func.into()];
let instance =
Instance::new(&module, imports.as_slice()).expect("failed to instantiate module");
let exports = instance.exports();
assert!(!exports.is_empty());
let run_func = exports[0]
.func()
.expect("expected a run func in the module");
*callback.other.borrow_mut() = Some(
exports[1]
.func()
.expect("expected an other func in the module")
.clone(),
);
run_func.call(&[]).expect("expected function not to trap");
}