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|
use std::str::FromStr;
use darling::export::NestedMeta;
use darling::FromMeta;
use proc_macro2::TokenStream;
use quote::quote;
use syn::{ReturnType, Type};
use crate::util::*;
enum Flavor {
Standard,
Wasm,
}
pub(crate) struct Arch {
default_entry: Option<&'static str>,
flavor: Flavor,
executor_required: bool,
}
pub static ARCH_AVR: Arch = Arch {
default_entry: Some("avr_device::entry"),
flavor: Flavor::Standard,
executor_required: false,
};
pub static ARCH_RISCV: Arch = Arch {
default_entry: Some("riscv_rt::entry"),
flavor: Flavor::Standard,
executor_required: false,
};
pub static ARCH_CORTEX_M: Arch = Arch {
default_entry: Some("cortex_m_rt::entry"),
flavor: Flavor::Standard,
executor_required: false,
};
pub static ARCH_SPIN: Arch = Arch {
default_entry: None,
flavor: Flavor::Standard,
executor_required: false,
};
pub static ARCH_STD: Arch = Arch {
default_entry: None,
flavor: Flavor::Standard,
executor_required: false,
};
pub static ARCH_WASM: Arch = Arch {
default_entry: Some("wasm_bindgen::prelude::wasm_bindgen(start)"),
flavor: Flavor::Wasm,
executor_required: false,
};
pub static ARCH_UNSPECIFIED: Arch = Arch {
default_entry: None,
flavor: Flavor::Standard,
executor_required: true,
};
#[derive(Debug, FromMeta, Default)]
struct Args {
#[darling(default)]
entry: Option<String>,
#[darling(default)]
executor: Option<String>,
}
pub fn run(args: TokenStream, item: TokenStream, arch: &Arch) -> TokenStream {
let mut errors = TokenStream::new();
// If any of the steps for this macro fail, we still want to expand to an item that is as close
// to the expected output as possible. This helps out IDEs such that completions and other
// related features keep working.
let f: ItemFn = match syn::parse2(item.clone()) {
Ok(x) => x,
Err(e) => return token_stream_with_error(item, e),
};
let args = match NestedMeta::parse_meta_list(args) {
Ok(x) => x,
Err(e) => return token_stream_with_error(item, e),
};
let args = match Args::from_list(&args) {
Ok(x) => x,
Err(e) => {
errors.extend(e.write_errors());
Args::default()
}
};
let fargs = f.sig.inputs.clone();
if f.sig.asyncness.is_none() {
error(&mut errors, &f.sig, "main function must be async");
}
if !f.sig.generics.params.is_empty() {
error(&mut errors, &f.sig, "main function must not be generic");
}
if !f.sig.generics.where_clause.is_none() {
error(&mut errors, &f.sig, "main function must not have `where` clauses");
}
if !f.sig.abi.is_none() {
error(&mut errors, &f.sig, "main function must not have an ABI qualifier");
}
if !f.sig.variadic.is_none() {
error(&mut errors, &f.sig, "main function must not be variadic");
}
match &f.sig.output {
ReturnType::Default => {}
ReturnType::Type(_, ty) => match &**ty {
Type::Tuple(tuple) if tuple.elems.is_empty() => {}
Type::Never(_) => {}
_ => error(
&mut errors,
&f.sig,
"main function must either not return a value, return `()` or return `!`",
),
},
}
if fargs.len() != 1 {
error(&mut errors, &f.sig, "main function must have 1 argument: the spawner.");
}
let entry = match (args.entry.as_deref(), arch.default_entry.as_deref()) {
(None, None) => TokenStream::new(),
(Some(x), _) | (None, Some(x)) if x == "" => TokenStream::new(),
(Some(x), _) | (None, Some(x)) => match TokenStream::from_str(x) {
Ok(x) => quote!(#[#x]),
Err(e) => {
error(&mut errors, &f.sig, e);
TokenStream::new()
}
},
};
let executor = match (args.executor.as_deref(), arch.executor_required) {
(None, true) => {
error(
&mut errors,
&f.sig,
"\
No architecture selected for embassy-executor. Make sure you've enabled one of the `arch-*` features in your Cargo.toml.
Alternatively, if you would like to use a custom executor implementation, specify it with the `executor` argument.
For example: `#[embassy_executor::main(entry = ..., executor = \"some_crate::Executor\")]",
);
""
}
(Some(x), _) => x,
(None, _) => "::embassy_executor::Executor",
};
let executor = TokenStream::from_str(executor).unwrap_or_else(|e| {
error(&mut errors, &f.sig, e);
TokenStream::new()
});
let f_body = f.body;
let out = &f.sig.output;
let (main_ret, mut main_body) = match arch.flavor {
Flavor::Standard => (
quote!(!),
quote! {
unsafe fn __make_static<T>(t: &mut T) -> &'static mut T {
::core::mem::transmute(t)
}
let mut executor = #executor::new();
let executor = unsafe { __make_static(&mut executor) };
executor.run(|spawner| {
spawner.must_spawn(__embassy_main(spawner));
})
},
),
Flavor::Wasm => (
quote!(Result<(), wasm_bindgen::JsValue>),
quote! {
let executor = ::std::boxed::Box::leak(::std::boxed::Box::new(#executor::new()));
executor.start(|spawner| {
spawner.must_spawn(__embassy_main(spawner));
});
Ok(())
},
),
};
let mut main_attrs = TokenStream::new();
for attr in f.attrs {
main_attrs.extend(quote!(#attr));
}
if !errors.is_empty() {
main_body = quote! {loop{}};
}
let result = quote! {
#[::embassy_executor::task()]
#[allow(clippy::future_not_send)]
async fn __embassy_main(#fargs) #out {
#f_body
}
#entry
#main_attrs
fn main() -> #main_ret {
#main_body
}
#errors
};
result
}
|
