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Remove long-outdated misc/rust crate (#2942)

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I had no idea this was still in the repository, much less building!
There are much different ways to use wasmtime in Rust nowadays, such as
the `wasmtime` crate!
This commit is contained in:
Alex Crichton
2021-05-27 12:05:35 -05:00
committed by GitHub
parent 76664fc73e
commit b90d7d6aed
8 changed files with 0 additions and 336 deletions
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19
Cargo.lock generated
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@@ -3795,25 +3795,6 @@ dependencies = [
"winapi", "winapi",
] ]
[[package]]
name = "wasmtime-rust"
version = "0.27.0"
dependencies = [
"anyhow",
"wasmtime",
"wasmtime-rust-macro",
"wasmtime-wasi",
]
[[package]]
name = "wasmtime-rust-macro"
version = "0.27.0"
dependencies = [
"proc-macro2",
"quote",
"syn",
]
[[package]] [[package]]
name = "wasmtime-wasi" name = "wasmtime-wasi"
version = "0.27.0" version = "0.27.0"

1
Cargo.toml
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@@ -74,7 +74,6 @@ members = [
"crates/c-api", "crates/c-api",
"crates/fuzzing", "crates/fuzzing",
"crates/misc/run-examples", "crates/misc/run-examples",
"crates/misc/rust",
"crates/wiggle", "crates/wiggle",
"crates/wiggle/generate", "crates/wiggle/generate",
"crates/wiggle/macro", "crates/wiggle/macro",

24
crates/misc/rust/Cargo.toml
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@@ -1,24 +0,0 @@
[package]
name = "wasmtime-rust"
version = "0.27.0"
authors = ["Alex Crichton <alex@alexcrichton.com>"]
description = "Rust extension for Wasmtime"
license = "Apache-2.0 WITH LLVM-exception"
categories = ["wasm"]
keywords = ["webassembly", "wasm"]
repository = "https://github.com/bytecodealliance/wasmtime"
readme = "README.md"
edition = "2018"
[lib]
test = false
doctest = false
[dependencies]
wasmtime-rust-macro = { path = "./macro", version = "0.27.0" }
wasmtime-wasi = { path = "../../wasi", version = "0.27.0" }
wasmtime = { path = "../../wasmtime", version = "0.27.0" }
anyhow = "1.0.19"
[badges]
maintenance = { status = "actively-developed" }

37
crates/misc/rust/README.md
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@@ -1,37 +0,0 @@
# `wasmtime-rust` - Using WebAssembly from Rust
This crate is intended to be an example of how to load WebAssembly files from a
native Rust application. You can always use `wasmtime` and its family of crates
directly, but the purpose of this crate is to provide an ergonomic macro:
```rust
#[wasmtime_rust::wasmtime]
trait WasmMarkdown {
fn render(&mut self, input: &str) -> String;
}
fn main() -> anyhow::Result<()> {
let mut markdown = WasmMarkdown::load_file("markdown.wasm")?;
println!("{}", markdown.render("# Hello, Rust!"));
Ok(())
}
```
The `wasmtime` macro defined in the `wasmtime-rust` crate is placed on a `trait`
which includes the set of functionality which a wasm module should export. In
this case we're expecting one `render` function which takes and returns a
string.
The macro expands to a `struct` with all of the methods on the trait (they must
all be `&mut self`) and one function called `load_file` to actually instantiate
the module.
Note that this macro is still in early stages of development, so error messages
aren't great yet and all functionality isn't supported yet.
## Missing features
Currently if the wasm module imports any symbols outside of the WASI namespace
the module will not load. It's intended that support for this will be added soon
though!

22
crates/misc/rust/macro/Cargo.toml
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@@ -1,22 +0,0 @@
[package]
name = "wasmtime-rust-macro"
version = "0.27.0"
authors = ["Alex Crichton <alex@alexcrichton.com>"]
description = "Macro support crate for wasmtime-rust"
license = "Apache-2.0 WITH LLVM-exception"
repository = "https://github.com/bytecodealliance/wasmtime"
readme = "README.md"
edition = "2018"
[lib]
proc-macro = true
test = false
doctest = false
[dependencies]
proc-macro2 = "1.0"
quote = "1.0"
syn = { version = "1.0", features = ['full'] }
[badges]
maintenance = { status = "actively-developed" }

5
crates/misc/rust/macro/README.md
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@@ -1,5 +0,0 @@
# `wasmtime-rust-macro`
This is the actual definition of the `#[wasmtime]` macro, but it's intended that
this crate isn't used directly but rather the `wasmtime-rust` crate is used
instead.

184
crates/misc/rust/macro/src/lib.rs
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@@ -1,184 +0,0 @@
extern crate proc_macro;
use proc_macro2::TokenStream;
use quote::quote;
use syn::spanned::Spanned;
#[proc_macro_attribute]
pub fn wasmtime(
_attr: proc_macro::TokenStream,
item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
let item = syn::parse_macro_input!(item as syn::ItemTrait);
expand(item).unwrap_or_else(|e| e.to_compile_error()).into()
}
fn expand(item: syn::ItemTrait) -> syn::Result<TokenStream> {
let definition = generate_struct(&item)?;
let load = generate_load(&item)?;
let methods = generate_methods(&item)?;
let name = &item.ident;
Ok(quote! {
#definition
impl #name {
#load
#methods
}
})
}
fn generate_struct(item: &syn::ItemTrait) -> syn::Result<TokenStream> {
let vis = &item.vis;
let name = &item.ident;
let root = root();
Ok(quote! {
#vis struct #name {
instance: #root::wasmtime::Instance,
data: #root::wasmtime_interface_types::ModuleData,
}
})
}
fn generate_load(item: &syn::ItemTrait) -> syn::Result<TokenStream> {
let vis = &item.vis;
let name = &item.ident;
let root = root();
Ok(quote! {
#vis fn load_file(path: impl AsRef<std::path::Path>) -> #root::anyhow::Result<#name> {
Self::load_bytes(std::fs::read(path)?)
}
#vis fn load_bytes(bytes: impl AsRef<[u8]>) -> #root::anyhow::Result<#name> {
use #root::wasmtime::{Config, Extern, Engine, Store, Instance, Module};
use #root::anyhow::{bail, format_err};
let store = Store::default();
let data = #root::wasmtime_interface_types::ModuleData::new(bytes.as_ref())?;
let module = Module::new(&engine, bytes.as_ref())?;
let mut imports: Vec<Extern> = Vec::new();
if let Some(module_name) = data.find_wasi_module_name() {
let wasi_cx = #root::wasmtime_wasi::WasiCtxBuilder::new().build();
let wasi = #root::wasmtime_wasi::Wasi::new(&store, wasi_cx);
for i in module.imports().iter() {
if i.module() != module_name {
bail!("unknown import module {}", i.module());
}
if let Some(export) = wasi.get_export(i.name()) {
imports.push(export.clone().into());
} else {
bail!("unknown import {}:{}", i.module(), i.name())
}
}
}
let instance =
Instance::new(&store, &module, &imports).map_err(|t| format_err!("instantiation trap: {:?}", t))?;
Ok(#name { instance, data })
}
})
}
fn generate_methods(item: &syn::ItemTrait) -> syn::Result<TokenStream> {
macro_rules! bail {
($e:expr, $($fmt:tt)*) => (
return Err(syn::Error::new($e.span(), format!($($fmt)*)));
)
}
let mut result = TokenStream::new();
let root = root();
let vis = &item.vis;
for item in item.items.iter() {
let method = match item {
syn::TraitItem::Method(f) => f,
other => bail!(other, "only methods are allowed"),
};
if let Some(e) = &method.default {
bail!(e, "cannot specify an implementation of methods");
}
if let Some(t) = &method.sig.constness {
bail!(t, "cannot be `const`");
}
if let Some(t) = &method.sig.asyncness {
bail!(t, "cannot be `async`");
}
match &method.sig.inputs.first() {
Some(syn::FnArg::Receiver(_)) => {}
Some(t) => bail!(t, "first arugment needs to be \"self\""),
None => bail!(
method.sig,
"trait method requires at least one argument which needs to be \"self\""
),
}
let mut args = Vec::new();
for arg in method.sig.inputs.iter() {
let arg = match arg {
syn::FnArg::Receiver(_) => continue,
syn::FnArg::Typed(arg) => arg,
};
let ident = match &*arg.pat {
syn::Pat::Ident(i) => i,
other => bail!(other, "must use bare idents for arguments"),
};
if let Some(t) = &ident.by_ref {
bail!(t, "arguments cannot bind by reference");
}
if let Some(t) = &ident.mutability {
bail!(t, "arguments cannot be mutable");
}
if let Some((_, t)) = &ident.subpat {
bail!(t, "arguments cannot have sub-bindings");
}
let ident = &ident.ident;
args.push(quote! {
#root::wasmtime_interface_types::Value::from(#ident)
});
}
let convert_ret = match &method.sig.output {
syn::ReturnType::Default => {
quote! {
<() as #root::FromVecValue>::from(results)
}
}
syn::ReturnType::Type(_, ty) => match &**ty {
syn::Type::Tuple(..) => {
quote! { <#ty as #root::FromVecValue>::from(results) }
}
_ => {
quote! { <(#ty,) as #root::FromVecValue>::from(results).map(|t| t.0) }
}
},
};
let sig = &method.sig;
let attrs = &method.attrs;
let name = &method.sig.ident;
result.extend(quote! {
#(#attrs)*
#vis #sig {
let args = [
#(#args),*
];
let results = self.data.invoke_export(
&self.instance,
stringify!(#name),
&args,
).expect("wasm execution failed");
#convert_ret.expect("failed to convert return type")
}
});
}
Ok(result)
}
fn root() -> TokenStream {
quote! { wasmtime_rust::__rt }
}

44
crates/misc/rust/src/lib.rs
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@@ -1,44 +0,0 @@
pub use wasmtime_rust_macro::wasmtime;
// modules used by the macro
#[doc(hidden)]
pub mod __rt {
pub use anyhow;
pub use wasmtime;
pub use wasmtime_wasi;
use std::convert::{TryFrom, TryInto};
pub trait FromVecValue: Sized {
fn from(list: Vec<wasmtime::Val>) -> anyhow::Result<Self>;
}
macro_rules! tuple {
($(($($a:ident),*),)*) => ($(
impl<$($a: TryFrom<wasmtime::Val>),*> FromVecValue for ($($a,)*)
where $(anyhow::Error: From<$a::Error>,)*
{
#[allow(non_snake_case)]
fn from(list: Vec<wasmtime::Val>) -> anyhow::Result<Self> {
let mut iter = list.into_iter();
$(
let $a = iter.next()
.ok_or_else(|| anyhow::format_err!("not enough values"))?
.try_into()?;
)*
if iter.next().is_some() {
anyhow::bail!("too many return values");
}
Ok(($($a,)*))
}
}
)*)
}
tuple! {
(),
(A),
(A, B),
(A, B, C),
}
}