https://github.com/sile/nowasm
No-std, no-unsafe and no-dependencies WebAssembly 1.0 runtime for Rust
https://github.com/sile/nowasm
nostd rust webassembly webassembly-runtime
Last synced: 6 months ago
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No-std, no-unsafe and no-dependencies WebAssembly 1.0 runtime for Rust
- Host: GitHub
- URL: https://github.com/sile/nowasm
- Owner: sile
- License: mit
- Created: 2024-06-11T12:24:27.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2024-07-16T10:08:04.000Z (over 1 year ago)
- Last Synced: 2025-01-08T05:25:58.909Z (about 1 year ago)
- Topics: nostd, rust, webassembly, webassembly-runtime
- Language: Rust
- Homepage:
- Size: 1.11 MB
- Stars: 45
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
nowasm
======
[](https://crates.io/crates/nowasm)
[](https://docs.rs/nowasm)
[](https://github.com/sile/nowasm/actions)
`nowasm` is a [WebAssembly 1.0][wasm-core-1] runtime that is implemented with no-std, no-unsafe and no-dependencies.
The goal is to provide a lightweight WebAssembly runtime that can be embedded wherever Rust is used, with a particular focus on Wasm-in-Wasm scenarios.
[wasm-core-1]: https://www.w3.org/TR/wasm-core-1/
TODO list until v0.1.0
----------------------
- [ ] Add validation phase (TBD)
- [ ] Add doc comments
- [ ] Add more tests
Supported Extensions
--------------------
`nowasm` supports the following extensions necessary to run WebAssembly binaries built with the latest stable Rust compiler.
- [sign-extension]
[sign-extension]: https://github.com/WebAssembly/sign-extension-ops/blob/master/proposals/sign-extension-ops/Overview.md
Examples
--------
Please execute the command `$ cargo build --target wasm32-unknown-unknown --example hello` to build the following "Hello World!" printing code ([examples/wasm/hello.rs](examples/wasm/hello.rs)) into a WebAssembly binary:
```rust
extern "C" {
fn print(s: *const u8, len: i32);
}
#[no_mangle]
pub fn hello() {
let msg = "Hello, World!\n";
unsafe {
print(msg.as_ptr(), msg.len() as i32);
}
}
```
Then, you can execute the `hello()` function via the following command:
```console
$ cargo run --example call_hello
Hello, World!
```
The code of [examples/call_hello.rs](examples/call_hello.rs) is as follows:
```rust
use nowasm::{Env, HostFunc, Module, Resolve, StdVectorFactory, Val};
pub fn main() {
let wasm_bytes = include_bytes!("../target/wasm32-unknown-unknown/debug/examples/hello.wasm");
let module = Module::::decode(wasm_bytes).expect("Failed to decode module");
let mut instance = module
.instantiate(Resolver)
.expect("Failed to instantiate module");
instance
.invoke("hello", &[])
.expect("Failed to invoke function");
}
struct Resolver;
impl Resolve for Resolver {
type HostFunc = Print;
fn resolve_func(&self, module: &str, name: &str) -> Option {
assert_eq!(module, "env");
assert_eq!(name, "print");
Some(Print)
}
}
struct Print;
impl HostFunc for Print {
fn invoke(&mut self, args: &[Val], env: &mut Env) -> Option {
let ptr = args[0].as_i32().expect("Not a i32") as usize;
let len = args[1].as_i32().expect("Not a i32") as usize;
let msg = std::str::from_utf8(&env.mem[ptr..ptr + len]).expect("Invalid utf8");
print!("{msg}");
None
}
}
```