embassy/embassy-macros/src/macros/task.rs
Dario Nieuwenhuis 408617266e Update Rust nightly.
Fixes a new opaque type error in the task macro.
Full error is "opaque type's hidden type cannot be another opaque type from the same scope".
This got disallwed by the lazy-TAIT PR: https://github.com/rust-lang/rust/pull/94081

Sadly there's now some weird type inference errors with pre-lazy-TAIT
nightlies, so support for those is dropped.
2022-04-24 04:24:08 +02:00

105 lines
3.3 KiB
Rust

use darling::FromMeta;
use proc_macro2::TokenStream;
use quote::{format_ident, quote};
use crate::util::ctxt::Ctxt;
use crate::util::path::ModulePrefix;
#[derive(Debug, FromMeta)]
struct Args {
#[darling(default)]
pool_size: Option<usize>,
#[darling(default)]
send: bool,
#[darling(default)]
embassy_prefix: ModulePrefix,
}
pub fn run(args: syn::AttributeArgs, mut f: syn::ItemFn) -> Result<TokenStream, TokenStream> {
let args = Args::from_list(&args).map_err(|e| e.write_errors())?;
let embassy_prefix = args.embassy_prefix.append("embassy");
let embassy_path = embassy_prefix.path();
let pool_size: usize = args.pool_size.unwrap_or(1);
let ctxt = Ctxt::new();
if f.sig.asyncness.is_none() {
ctxt.error_spanned_by(&f.sig, "task functions must be async");
}
if !f.sig.generics.params.is_empty() {
ctxt.error_spanned_by(&f.sig, "task functions must not be generic");
}
if pool_size < 1 {
ctxt.error_spanned_by(&f.sig, "pool_size must be 1 or greater");
}
let mut arg_names: syn::punctuated::Punctuated<syn::Ident, syn::Token![,]> =
syn::punctuated::Punctuated::new();
let mut fargs = f.sig.inputs.clone();
for arg in fargs.iter_mut() {
match arg {
syn::FnArg::Receiver(_) => {
ctxt.error_spanned_by(arg, "task functions must not have receiver arguments");
}
syn::FnArg::Typed(t) => match t.pat.as_mut() {
syn::Pat::Ident(i) => {
arg_names.push(i.ident.clone());
i.mutability = None;
}
_ => {
ctxt.error_spanned_by(
arg,
"pattern matching in task arguments is not yet supporteds",
);
}
},
}
}
ctxt.check()?;
let task_ident = f.sig.ident.clone();
let task_inner_ident = format_ident!("__{}_task", task_ident);
let future_ident = format_ident!("__{}_Future", task_ident);
let pool_ident = format_ident!("__{}_POOL", task_ident);
let new_ts_ident = format_ident!("__{}_NEW_TASKSTORAGE", task_ident);
let visibility = &f.vis;
f.sig.ident = task_inner_ident.clone();
let impl_ty = if args.send {
quote!(impl ::core::future::Future + Send + 'static)
} else {
quote!(impl ::core::future::Future + 'static)
};
let attrs = &f.attrs;
let spawn_token = quote!(#embassy_path::executor::SpawnToken);
let task_storage = quote!(#embassy_path::executor::raw::TaskStorage);
let result = quote! {
#[allow(non_camel_case_types)]
type #future_ident = #impl_ty;
#(#attrs)*
#visibility fn #task_ident(#fargs) -> #spawn_token<#future_ident> {
#f
#[allow(non_upper_case_globals)]
#[allow(clippy::declare_interior_mutable_const)]
const #new_ts_ident: #task_storage<#future_ident> = #task_storage::new();
#[allow(non_upper_case_globals)]
static #pool_ident: [#task_storage<#future_ident>; #pool_size] = [#new_ts_ident; #pool_size];
unsafe { #task_storage::spawn_pool(&#pool_ident, move || #task_inner_ident(#arg_names)) }
}
};
Ok(result)
}