async_trait/
args.rs

1use proc_macro2::Span;
2use syn::parse::{Error, Parse, ParseStream, Result};
3use syn::Token;
4
5#[derive(Copy, Clone)]
6pub struct Args {
7    pub local: bool,
8}
9
10mod kw {
11    syn::custom_keyword!(Send);
12}
13
14impl Parse for Args {
15    fn parse(input: ParseStream) -> Result<Self> {
16        match try_parse(input) {
17            Ok(args) if input.is_empty() => Ok(args),
18            _ => Err(error()),
19        }
20    }
21}
22
23fn try_parse(input: ParseStream) -> Result<Args> {
24    if input.peek(Token![?]) {
25        input.parse::<Token![?]>()?;
26        input.parse::<kw::Send>()?;
27        Ok(Args { local: true })
28    } else {
29        Ok(Args { local: false })
30    }
31}
32
33fn error() -> Error {
34    let msg = "expected #[async_trait] or #[async_trait(?Send)]";
35    Error::new(Span::call_site(), msg)
36}
async_trait/args.rs

async_trait/
args.rs
