126 lines
4.2 KiB
Rust
126 lines
4.2 KiB
Rust
use darling::export::NestedMeta;
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use darling::FromMeta;
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use proc_macro2::{Span, TokenStream};
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use quote::{format_ident, quote};
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use syn::{parse_quote, Expr, ExprLit, ItemFn, Lit, LitInt, ReturnType, Type};
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use crate::util::ctxt::Ctxt;
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#[derive(Debug, FromMeta)]
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struct Args {
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#[darling(default)]
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pool_size: Option<syn::Expr>,
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}
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pub fn run(args: &[NestedMeta], f: syn::ItemFn) -> Result<TokenStream, TokenStream> {
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let args = Args::from_list(args).map_err(|e| e.write_errors())?;
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let pool_size = args.pool_size.unwrap_or(Expr::Lit(ExprLit {
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attrs: vec![],
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lit: Lit::Int(LitInt::new("1", Span::call_site())),
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}));
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let ctxt = Ctxt::new();
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if f.sig.asyncness.is_none() {
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ctxt.error_spanned_by(&f.sig, "task functions must be async");
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}
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if !f.sig.generics.params.is_empty() {
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ctxt.error_spanned_by(&f.sig, "task functions must not be generic");
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}
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if !f.sig.generics.where_clause.is_none() {
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ctxt.error_spanned_by(&f.sig, "task functions must not have `where` clauses");
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}
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if !f.sig.abi.is_none() {
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ctxt.error_spanned_by(&f.sig, "task functions must not have an ABI qualifier");
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}
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if !f.sig.variadic.is_none() {
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ctxt.error_spanned_by(&f.sig, "task functions must not be variadic");
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}
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match &f.sig.output {
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ReturnType::Default => {}
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ReturnType::Type(_, ty) => match &**ty {
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Type::Tuple(tuple) if tuple.elems.is_empty() => {}
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Type::Never(_) => {}
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_ => ctxt.error_spanned_by(
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&f.sig,
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"task functions must either not return a value, return `()` or return `!`",
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),
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},
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}
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let mut args = Vec::new();
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let mut fargs = f.sig.inputs.clone();
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for arg in fargs.iter_mut() {
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match arg {
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syn::FnArg::Receiver(_) => {
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ctxt.error_spanned_by(arg, "task functions must not have receiver arguments");
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}
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syn::FnArg::Typed(t) => match t.pat.as_mut() {
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syn::Pat::Ident(id) => {
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id.mutability = None;
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args.push((id.clone(), t.attrs.clone()));
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}
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_ => {
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ctxt.error_spanned_by(arg, "pattern matching in task arguments is not yet supported");
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}
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},
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}
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}
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ctxt.check()?;
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let task_ident = f.sig.ident.clone();
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let task_inner_ident = format_ident!("__{}_task", task_ident);
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let mut task_inner = f;
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let visibility = task_inner.vis.clone();
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task_inner.vis = syn::Visibility::Inherited;
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task_inner.sig.ident = task_inner_ident.clone();
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// assemble the original input arguments,
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// including any attributes that may have
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// been applied previously
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let mut full_args = Vec::new();
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for (arg, cfgs) in args {
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full_args.push(quote!(
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#(#cfgs)*
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#arg
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));
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}
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#[cfg(feature = "nightly")]
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let mut task_outer: ItemFn = parse_quote! {
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#visibility fn #task_ident(#fargs) -> ::embassy_executor::SpawnToken<impl Sized> {
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type Fut = impl ::core::future::Future + 'static;
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const POOL_SIZE: usize = #pool_size;
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static POOL: ::embassy_executor::raw::TaskPool<Fut, POOL_SIZE> = ::embassy_executor::raw::TaskPool::new();
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unsafe { POOL._spawn_async_fn(move || #task_inner_ident(#(#full_args,)*)) }
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}
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};
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#[cfg(not(feature = "nightly"))]
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let mut task_outer: ItemFn = parse_quote! {
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#visibility fn #task_ident(#fargs) -> ::embassy_executor::SpawnToken<impl Sized> {
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const POOL_SIZE: usize = #pool_size;
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static POOL: ::embassy_executor::_export::TaskPoolRef = ::embassy_executor::_export::TaskPoolRef::new();
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unsafe { POOL.get::<_, POOL_SIZE>()._spawn_async_fn(move || #task_inner_ident(#(#full_args,)*)) }
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}
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};
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task_outer.attrs.append(&mut task_inner.attrs.clone());
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let result = quote! {
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// This is the user's task function, renamed.
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// We put it outside the #task_ident fn below, because otherwise
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// the items defined there (such as POOL) would be in scope
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// in the user's code.
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#[doc(hidden)]
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#task_inner
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#task_outer
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};
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Ok(result)
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}
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