macros: cleanup, make work in stable.

This commit is contained in:
Dario Nieuwenhuis 2022-02-12 00:11:15 +01:00
parent 6c925b2342
commit 611961b499
13 changed files with 462 additions and 547 deletions

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@ -1,11 +0,0 @@
use crate::path::ModulePrefix;
use proc_macro2::TokenStream;
use quote::quote;
pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream {
let embassy_nrf_path = embassy_prefix.append("embassy_nrf").path();
quote!(
let p = #embassy_nrf_path::init(#config);
)
}

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@ -1,10 +0,0 @@
use crate::path::ModulePrefix;
use proc_macro2::TokenStream;
use quote::quote;
pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream {
let embassy_rp_path = embassy_prefix.append("embassy_rp").path();
quote!(
let p = #embassy_rp_path::init(#config);
)
}

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@ -1,11 +0,0 @@
use crate::path::ModulePrefix;
use proc_macro2::TokenStream;
use quote::quote;
pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream {
let embassy_stm32_path = embassy_prefix.append("embassy_stm32").path();
quote!(
let p = #embassy_stm32_path::init(#config);
)
}

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@ -1,228 +1,39 @@
#![feature(proc_macro_diagnostic)]
extern crate proc_macro;
use darling::FromMeta;
use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::{format_ident, quote};
use std::iter;
use syn::spanned::Spanned;
use syn::{parse, Type, Visibility};
use syn::{ItemFn, ReturnType};
mod path;
use path::ModulePrefix;
#[derive(Debug, FromMeta)]
struct TaskArgs {
#[darling(default)]
pool_size: Option<usize>,
#[darling(default)]
send: bool,
#[darling(default)]
embassy_prefix: ModulePrefix,
}
mod macros;
mod util;
use macros::*;
#[proc_macro_attribute]
pub fn task(args: TokenStream, item: TokenStream) -> TokenStream {
let macro_args = syn::parse_macro_input!(args as syn::AttributeArgs);
let mut task_fn = syn::parse_macro_input!(item as syn::ItemFn);
let args = syn::parse_macro_input!(args as syn::AttributeArgs);
let f = syn::parse_macro_input!(item as syn::ItemFn);
let macro_args = match TaskArgs::from_list(&macro_args) {
Ok(v) => v,
Err(e) => {
return TokenStream::from(e.write_errors());
}
};
let embassy_prefix = macro_args.embassy_prefix.append("embassy");
let embassy_path = embassy_prefix.path();
let pool_size: usize = macro_args.pool_size.unwrap_or(1);
let mut fail = false;
if task_fn.sig.asyncness.is_none() {
task_fn
.sig
.span()
.unwrap()
.error("task functions must be async")
.emit();
fail = true;
}
if !task_fn.sig.generics.params.is_empty() {
task_fn
.sig
.span()
.unwrap()
.error("task functions must not be generic")
.emit();
fail = true;
}
if pool_size < 1 {
return parse::Error::new(Span::call_site(), "pool_size must be 1 or greater")
.to_compile_error()
.into();
}
let mut arg_names: syn::punctuated::Punctuated<syn::Ident, syn::Token![,]> =
syn::punctuated::Punctuated::new();
let mut args = task_fn.sig.inputs.clone();
for arg in args.iter_mut() {
match arg {
syn::FnArg::Receiver(_) => {
arg.span()
.unwrap()
.error("task functions must not have receiver arguments")
.emit();
fail = true;
}
syn::FnArg::Typed(t) => match t.pat.as_mut() {
syn::Pat::Ident(i) => {
arg_names.push(i.ident.clone());
i.mutability = None;
}
_ => {
arg.span()
.unwrap()
.error("pattern matching in task arguments is not yet supporteds")
.emit();
fail = true;
}
},
}
}
if fail {
return TokenStream::new();
}
let name = task_fn.sig.ident.clone();
let visibility = &task_fn.vis;
task_fn.sig.ident = format_ident!("task");
let impl_ty = if macro_args.send {
quote!(impl ::core::future::Future + Send + 'static)
} else {
quote!(impl ::core::future::Future + 'static)
};
let attrs = &task_fn.attrs;
let result = quote! {
#(#attrs)*
#visibility fn #name(#args) -> #embassy_path::executor::SpawnToken<#impl_ty> {
use #embassy_path::executor::raw::TaskStorage;
#task_fn
type F = #impl_ty;
#[allow(clippy::declare_interior_mutable_const)]
const NEW_TASK: TaskStorage<F> = TaskStorage::new();
static POOL: [TaskStorage<F>; #pool_size] = [NEW_TASK; #pool_size];
unsafe { TaskStorage::spawn_pool(&POOL, move || task(#arg_names)) }
}
};
result.into()
task::run(args, f).unwrap_or_else(|x| x).into()
}
#[proc_macro_attribute]
pub fn interrupt(args: TokenStream, input: TokenStream) -> TokenStream {
let mut f: ItemFn = syn::parse(input).expect("`#[interrupt]` must be applied to a function");
if !args.is_empty() {
return parse::Error::new(Span::call_site(), "This attribute accepts no arguments")
.to_compile_error()
.into();
pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
let args = syn::parse_macro_input!(args as syn::AttributeArgs);
let f = syn::parse_macro_input!(item as syn::ItemFn);
main::run(args, f).unwrap_or_else(|x| x).into()
}
let fspan = f.span();
let ident = f.sig.ident.clone();
let ident_s = ident.to_string();
// XXX should we blacklist other attributes?
let valid_signature = f.sig.constness.is_none()
&& f.vis == Visibility::Inherited
&& f.sig.abi.is_none()
&& f.sig.inputs.is_empty()
&& f.sig.generics.params.is_empty()
&& f.sig.generics.where_clause.is_none()
&& f.sig.variadic.is_none()
&& match f.sig.output {
ReturnType::Default => true,
ReturnType::Type(_, ref ty) => match **ty {
Type::Tuple(ref tuple) => tuple.elems.is_empty(),
Type::Never(..) => true,
_ => false,
},
};
if !valid_signature {
return parse::Error::new(
fspan,
"`#[interrupt]` handlers must have signature `[unsafe] fn() [-> !]`",
)
.to_compile_error()
.into();
}
f.block.stmts = iter::once(
syn::parse2(quote! {{
// Check that this interrupt actually exists
let __irq_exists_check: interrupt::#ident;
}})
.unwrap(),
)
.chain(f.block.stmts)
.collect();
quote!(
#[doc(hidden)]
#[export_name = #ident_s]
#[allow(non_snake_case)]
#f
)
.into()
#[proc_macro_attribute]
pub fn interrupt(args: TokenStream, item: TokenStream) -> TokenStream {
let args = syn::parse_macro_input!(args as syn::AttributeArgs);
let f = syn::parse_macro_input!(item as syn::ItemFn);
interrupt::run(args, f).unwrap_or_else(|x| x).into()
}
#[proc_macro]
pub fn interrupt_declare(item: TokenStream) -> TokenStream {
let name = syn::parse_macro_input!(item as syn::Ident);
let name = format_ident!("{}", name);
let name_interrupt = format_ident!("{}", name);
let name_handler = format!("__EMBASSY_{}_HANDLER", name);
let result = quote! {
#[allow(non_camel_case_types)]
pub struct #name_interrupt(());
unsafe impl ::embassy::interrupt::Interrupt for #name_interrupt {
type Priority = crate::interrupt::Priority;
fn number(&self) -> u16 {
use cortex_m::interrupt::InterruptNumber;
let irq = InterruptEnum::#name;
irq.number() as u16
}
unsafe fn steal() -> Self {
Self(())
}
unsafe fn __handler(&self) -> &'static ::embassy::interrupt::Handler {
#[export_name = #name_handler]
static HANDLER: ::embassy::interrupt::Handler = ::embassy::interrupt::Handler::new();
&HANDLER
}
interrupt_declare::run(name).unwrap_or_else(|x| x).into()
}
unsafe impl ::embassy::util::Unborrow for #name_interrupt {
type Target = #name_interrupt;
unsafe fn unborrow(self) -> #name_interrupt {
self
}
}
};
result.into()
}
/// # interrupt_take procedural macro
///
/// core::panic! is used as a default way to panic in this macro as there is no sensible way of enabling/disabling defmt for macro generation.
@ -231,312 +42,5 @@ pub fn interrupt_declare(item: TokenStream) -> TokenStream {
#[proc_macro]
pub fn interrupt_take(item: TokenStream) -> TokenStream {
let name = syn::parse_macro_input!(item as syn::Ident);
let name = format!("{}", name);
let name_interrupt = format_ident!("{}", name);
let name_handler = format!("__EMBASSY_{}_HANDLER", name);
let result = quote! {
{
#[allow(non_snake_case)]
#[export_name = #name]
pub unsafe extern "C" fn trampoline() {
extern "C" {
#[link_name = #name_handler]
static HANDLER: ::embassy::interrupt::Handler;
}
let func = HANDLER.func.load(::embassy::export::atomic::Ordering::Relaxed);
let ctx = HANDLER.ctx.load(::embassy::export::atomic::Ordering::Relaxed);
let func: fn(*mut ()) = ::core::mem::transmute(func);
func(ctx)
}
static TAKEN: ::embassy::export::atomic::AtomicBool = ::embassy::export::atomic::AtomicBool::new(false);
if TAKEN.compare_exchange(false, true, ::embassy::export::atomic::Ordering::AcqRel, ::embassy::export::atomic::Ordering::Acquire).is_err() {
core::panic!("IRQ Already taken");
}
let irq: interrupt::#name_interrupt = unsafe { ::core::mem::transmute(()) };
irq
}
};
result.into()
}
#[cfg(feature = "stm32")]
#[path = "chip/stm32.rs"]
mod chip;
#[cfg(feature = "nrf")]
#[path = "chip/nrf.rs"]
mod chip;
#[cfg(feature = "rp")]
#[path = "chip/rp.rs"]
mod chip;
#[cfg(any(
feature = "nrf",
feature = "rp",
feature = "stm32",
feature = "wasm",
feature = "std"
))]
#[derive(Debug, FromMeta)]
struct MainArgs {
#[darling(default)]
embassy_prefix: ModulePrefix,
#[allow(unused)]
#[darling(default)]
config: Option<syn::LitStr>,
}
#[cfg(any(feature = "nrf", feature = "rp", feature = "stm32"))]
#[proc_macro_attribute]
pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
let macro_args = syn::parse_macro_input!(args as syn::AttributeArgs);
let task_fn = syn::parse_macro_input!(item as syn::ItemFn);
let macro_args = match MainArgs::from_list(&macro_args) {
Ok(v) => v,
Err(e) => {
return TokenStream::from(e.write_errors());
}
};
let mut fail = false;
if task_fn.sig.asyncness.is_none() {
task_fn
.sig
.span()
.unwrap()
.error("task functions must be async")
.emit();
fail = true;
}
if !task_fn.sig.generics.params.is_empty() {
task_fn
.sig
.span()
.unwrap()
.error("main function must not be generic")
.emit();
fail = true;
}
let args = task_fn.sig.inputs.clone();
if args.len() != 2 {
task_fn
.sig
.span()
.unwrap()
.error("main function must have 2 arguments")
.emit();
fail = true;
}
if fail {
return TokenStream::new();
}
let embassy_prefix = macro_args.embassy_prefix;
let embassy_prefix_lit = embassy_prefix.literal();
let embassy_path = embassy_prefix.append("embassy").path();
let task_fn_body = task_fn.block;
let config = macro_args
.config
.map(|s| s.parse::<syn::Expr>().unwrap())
.unwrap_or_else(|| {
syn::Expr::Verbatim(quote! {
Default::default()
})
});
let chip_setup = chip::generate(&embassy_prefix, config);
let result = quote! {
#[#embassy_path::task(embassy_prefix = #embassy_prefix_lit)]
async fn __embassy_main(#args) {
#task_fn_body
}
#[cortex_m_rt::entry]
fn main() -> ! {
unsafe fn make_static<T>(t: &mut T) -> &'static mut T {
::core::mem::transmute(t)
}
#chip_setup
let mut executor = #embassy_path::executor::Executor::new();
let executor = unsafe { make_static(&mut executor) };
executor.run(|spawner| {
spawner.must_spawn(__embassy_main(spawner, p));
})
}
};
result.into()
}
#[cfg(feature = "std")]
#[proc_macro_attribute]
pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
let macro_args = syn::parse_macro_input!(args as syn::AttributeArgs);
let task_fn = syn::parse_macro_input!(item as syn::ItemFn);
let macro_args = match MainArgs::from_list(&macro_args) {
Ok(v) => v,
Err(e) => {
return TokenStream::from(e.write_errors());
}
};
let embassy_path = macro_args.embassy_prefix.append("embassy");
let mut fail = false;
if task_fn.sig.asyncness.is_none() {
task_fn
.sig
.span()
.unwrap()
.error("task functions must be async")
.emit();
fail = true;
}
if !task_fn.sig.generics.params.is_empty() {
task_fn
.sig
.span()
.unwrap()
.error("main function must not be generic")
.emit();
fail = true;
}
let args = task_fn.sig.inputs.clone();
if args.len() != 1 {
task_fn
.sig
.span()
.unwrap()
.error("main function must have one argument")
.emit();
fail = true;
}
if fail {
return TokenStream::new();
}
let task_fn_body = task_fn.block.clone();
let embassy_path = embassy_path.path();
let embassy_prefix_lit = macro_args.embassy_prefix.literal();
let result = quote! {
#[#embassy_path::task(embassy_prefix = #embassy_prefix_lit)]
async fn __embassy_main(#args) {
#task_fn_body
}
fn main() -> ! {
unsafe fn make_static<T>(t: &mut T) -> &'static mut T {
::core::mem::transmute(t)
}
let mut executor = #embassy_path::executor::Executor::new();
let executor = unsafe { make_static(&mut executor) };
executor.run(|spawner| {
spawner.spawn(__embassy_main(spawner)).unwrap();
})
}
};
result.into()
}
#[cfg(feature = "wasm")]
#[proc_macro_attribute]
pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
let macro_args = syn::parse_macro_input!(args as syn::AttributeArgs);
let task_fn = syn::parse_macro_input!(item as syn::ItemFn);
let macro_args = match MainArgs::from_list(&macro_args) {
Ok(v) => v,
Err(e) => {
return TokenStream::from(e.write_errors());
}
};
let embassy_path = macro_args.embassy_prefix.append("embassy");
let mut fail = false;
if task_fn.sig.asyncness.is_none() {
task_fn
.sig
.span()
.unwrap()
.error("task functions must be async")
.emit();
fail = true;
}
if !task_fn.sig.generics.params.is_empty() {
task_fn
.sig
.span()
.unwrap()
.error("main function must not be generic")
.emit();
fail = true;
}
let args = task_fn.sig.inputs.clone();
if args.len() != 1 {
task_fn
.sig
.span()
.unwrap()
.error("main function must have one argument")
.emit();
fail = true;
}
if fail {
return TokenStream::new();
}
let task_fn_body = task_fn.block.clone();
let embassy_path = embassy_path.path();
let embassy_prefix_lit = macro_args.embassy_prefix.literal();
let result = quote! {
#[#embassy_path::task(embassy_prefix = #embassy_prefix_lit)]
async fn __embassy_main(#args) {
#task_fn_body
}
use wasm_bindgen::prelude::*;
#[wasm_bindgen(start)]
pub fn main() -> Result<(), JsValue> {
static EXECUTOR: #embassy_path::util::Forever<#embassy_path::executor::Executor> = #embassy_path::util::Forever::new();
let executor = EXECUTOR.put(#embassy_path::executor::Executor::new());
executor.start(|spawner| {
spawner.spawn(__embassy_main(spawner)).unwrap();
});
Ok(())
}
};
result.into()
interrupt_take::run(name).unwrap_or_else(|x| x).into()
}

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@ -0,0 +1,66 @@
use darling::FromMeta;
use proc_macro2::TokenStream;
use quote::quote;
use std::iter;
use syn::ReturnType;
use syn::{Type, Visibility};
use crate::util::ctxt::Ctxt;
#[derive(Debug, FromMeta)]
struct Args {}
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 ident = f.sig.ident.clone();
let ident_s = ident.to_string();
// XXX should we blacklist other attributes?
let valid_signature = f.sig.constness.is_none()
&& f.vis == Visibility::Inherited
&& f.sig.abi.is_none()
&& f.sig.inputs.is_empty()
&& f.sig.generics.params.is_empty()
&& f.sig.generics.where_clause.is_none()
&& f.sig.variadic.is_none()
&& match f.sig.output {
ReturnType::Default => true,
ReturnType::Type(_, ref ty) => match **ty {
Type::Tuple(ref tuple) => tuple.elems.is_empty(),
Type::Never(..) => true,
_ => false,
},
};
let ctxt = Ctxt::new();
if !valid_signature {
ctxt.error_spanned_by(
&f.sig,
"`#[interrupt]` handlers must have signature `[unsafe] fn() [-> !]`",
);
}
ctxt.check()?;
f.block.stmts = iter::once(
syn::parse2(quote! {{
// Check that this interrupt actually exists
let __irq_exists_check: interrupt::#ident;
}})
.unwrap(),
)
.chain(f.block.stmts)
.collect();
let result = quote!(
#[doc(hidden)]
#[export_name = #ident_s]
#[allow(non_snake_case)]
#f
);
Ok(result)
}

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@ -0,0 +1,37 @@
use proc_macro2::TokenStream;
use quote::{format_ident, quote};
pub fn run(name: syn::Ident) -> Result<TokenStream, TokenStream> {
let name = format_ident!("{}", name);
let name_interrupt = format_ident!("{}", name);
let name_handler = format!("__EMBASSY_{}_HANDLER", name);
let result = quote! {
#[allow(non_camel_case_types)]
pub struct #name_interrupt(());
unsafe impl ::embassy::interrupt::Interrupt for #name_interrupt {
type Priority = crate::interrupt::Priority;
fn number(&self) -> u16 {
use cortex_m::interrupt::InterruptNumber;
let irq = InterruptEnum::#name;
irq.number() as u16
}
unsafe fn steal() -> Self {
Self(())
}
unsafe fn __handler(&self) -> &'static ::embassy::interrupt::Handler {
#[export_name = #name_handler]
static HANDLER: ::embassy::interrupt::Handler = ::embassy::interrupt::Handler::new();
&HANDLER
}
}
unsafe impl ::embassy::util::Unborrow for #name_interrupt {
type Target = #name_interrupt;
unsafe fn unborrow(self) -> #name_interrupt {
self
}
}
};
Ok(result)
}

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@ -0,0 +1,36 @@
use proc_macro2::TokenStream;
use quote::{format_ident, quote};
pub fn run(name: syn::Ident) -> Result<TokenStream, TokenStream> {
let name = format!("{}", name);
let name_interrupt = format_ident!("{}", name);
let name_handler = format!("__EMBASSY_{}_HANDLER", name);
let result = quote! {
{
#[allow(non_snake_case)]
#[export_name = #name]
pub unsafe extern "C" fn trampoline() {
extern "C" {
#[link_name = #name_handler]
static HANDLER: ::embassy::interrupt::Handler;
}
let func = HANDLER.func.load(::embassy::export::atomic::Ordering::Relaxed);
let ctx = HANDLER.ctx.load(::embassy::export::atomic::Ordering::Relaxed);
let func: fn(*mut ()) = ::core::mem::transmute(func);
func(ctx)
}
static TAKEN: ::embassy::export::atomic::AtomicBool = ::embassy::export::atomic::AtomicBool::new(false);
if TAKEN.compare_exchange(false, true, ::embassy::export::atomic::Ordering::AcqRel, ::embassy::export::atomic::Ordering::Acquire).is_err() {
core::panic!("IRQ Already taken");
}
let irq: interrupt::#name_interrupt = unsafe { ::core::mem::transmute(()) };
irq
}
};
Ok(result)
}

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@ -0,0 +1,135 @@
use darling::FromMeta;
use proc_macro2::TokenStream;
use quote::quote;
use crate::util::ctxt::Ctxt;
use crate::util::path::ModulePrefix;
#[cfg(feature = "stm32")]
const HAL: Option<&str> = Some("embassy_stm32");
#[cfg(feature = "nrf")]
const HAL: Option<&str> = Some("embassy_nrf");
#[cfg(feature = "rp")]
const HAL: Option<&str> = Some("embassy_rp");
#[cfg(not(any(feature = "stm32", feature = "nrf", feature = "rp")))]
const HAL: Option<&str> = None;
#[derive(Debug, FromMeta)]
struct Args {
#[darling(default)]
embassy_prefix: ModulePrefix,
#[allow(unused)]
#[darling(default)]
config: Option<syn::LitStr>,
}
pub fn run(args: syn::AttributeArgs, f: syn::ItemFn) -> Result<TokenStream, TokenStream> {
let args = Args::from_list(&args).map_err(|e| e.write_errors())?;
let fargs = f.sig.inputs.clone();
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 HAL.is_some() && fargs.len() != 2 {
ctxt.error_spanned_by(&f.sig, "main function must have 2 arguments");
}
if HAL.is_none() && fargs.len() != 1 {
ctxt.error_spanned_by(&f.sig, "main function must have 2 arguments");
}
ctxt.check()?;
let embassy_prefix = args.embassy_prefix;
let embassy_prefix_lit = embassy_prefix.literal();
let embassy_path = embassy_prefix.append("embassy").path();
let f_body = f.block;
#[cfg(feature = "wasm")]
let main = quote! {
#[wasm_bindgen::prelude::wasm_bindgen(start)]
pub fn main() -> Result<(), wasm_bindgen::JsValue> {
static EXECUTOR: #embassy_path::util::Forever<#embassy_path::executor::Executor> = #embassy_path::util::Forever::new();
let executor = EXECUTOR.put(#embassy_path::executor::Executor::new());
executor.start(|spawner| {
spawner.spawn(__embassy_main(spawner)).unwrap();
});
Ok(())
}
};
#[cfg(all(feature = "std", not(feature = "wasm")))]
let main = quote! {
fn main() -> ! {
let mut executor = #embassy_path::executor::Executor::new();
let executor = unsafe { __make_static(&mut executor) };
executor.run(|spawner| {
spawner.must_spawn(__embassy_main(spawner));
})
}
};
#[cfg(all(not(feature = "std"), not(feature = "wasm")))]
let main = {
let config = args
.config
.map(|s| s.parse::<syn::Expr>().unwrap())
.unwrap_or_else(|| {
syn::Expr::Verbatim(quote! {
Default::default()
})
});
let (hal_setup, peris_arg) = match HAL {
Some(hal) => {
let embassy_hal_path = embassy_prefix.append(hal).path();
(
quote!(
let p = #embassy_hal_path::init(#config);
),
quote!(p),
)
}
None => (quote!(), quote!()),
};
quote! {
#[cortex_m_rt::entry]
fn main() -> ! {
#hal_setup
let mut executor = #embassy_path::executor::Executor::new();
let executor = unsafe { __make_static(&mut executor) };
executor.run(|spawner| {
spawner.must_spawn(__embassy_main(spawner, #peris_arg));
})
}
}
};
let result = quote! {
#[#embassy_path::task(embassy_prefix = #embassy_prefix_lit)]
async fn __embassy_main(#fargs) {
#f_body
}
unsafe fn __make_static<T>(t: &mut T) -> &'static mut T {
::core::mem::transmute(t)
}
#main
};
Ok(result)
}

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pub mod interrupt;
pub mod interrupt_declare;
pub mod interrupt_take;
pub mod main;
pub mod task;

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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 name = f.sig.ident.clone();
let visibility = &f.vis;
f.sig.ident = format_ident!("task");
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 result = quote! {
#(#attrs)*
#visibility fn #name(#fargs) -> #embassy_path::executor::SpawnToken<#impl_ty> {
use #embassy_path::executor::raw::TaskStorage;
#f
type F = #impl_ty;
#[allow(clippy::declare_interior_mutable_const)]
const NEW_TASK: TaskStorage<F> = TaskStorage::new();
static POOL: [TaskStorage<F>; #pool_size] = [NEW_TASK; #pool_size];
unsafe { TaskStorage::spawn_pool(&POOL, move || task(#arg_names)) }
}
};
Ok(result)
}

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// nifty utility borrowed from serde :)
// https://github.com/serde-rs/serde/blob/master/serde_derive/src/internals/ctxt.rs
use proc_macro2::TokenStream;
use quote::{quote, ToTokens};
use std::cell::RefCell;
use std::fmt::Display;
use std::thread;
use syn;
/// A type to collect errors together and format them.
///
/// Dropping this object will cause a panic. It must be consumed using `check`.
///
/// References can be shared since this type uses run-time exclusive mut checking.
#[derive(Default)]
pub struct Ctxt {
// The contents will be set to `None` during checking. This is so that checking can be
// enforced.
errors: RefCell<Option<Vec<syn::Error>>>,
}
impl Ctxt {
/// Create a new context object.
///
/// This object contains no errors, but will still trigger a panic if it is not `check`ed.
pub fn new() -> Self {
Ctxt {
errors: RefCell::new(Some(Vec::new())),
}
}
/// Add an error to the context object with a tokenenizable object.
///
/// The object is used for spanning in error messages.
pub fn error_spanned_by<A: ToTokens, T: Display>(&self, obj: A, msg: T) {
self.errors
.borrow_mut()
.as_mut()
.unwrap()
// Curb monomorphization from generating too many identical methods.
.push(syn::Error::new_spanned(obj.into_token_stream(), msg));
}
/// Add one of Syn's parse errors.
#[allow(unused)]
pub fn syn_error(&self, err: syn::Error) {
self.errors.borrow_mut().as_mut().unwrap().push(err);
}
/// Consume this object, producing a formatted error string if there are errors.
pub fn check(self) -> Result<(), TokenStream> {
let errors = self.errors.borrow_mut().take().unwrap();
match errors.len() {
0 => Ok(()),
_ => Err(to_compile_errors(errors)),
}
}
}
fn to_compile_errors(errors: Vec<syn::Error>) -> proc_macro2::TokenStream {
let compile_errors = errors.iter().map(syn::Error::to_compile_error);
quote!(#(#compile_errors)*)
}
impl Drop for Ctxt {
fn drop(&mut self) {
if !thread::panicking() && self.errors.borrow().is_some() {
panic!("forgot to check for errors");
}
}
}

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pub mod ctxt;
pub mod path;