Import async-trait crate.
Bug: 164106399
Bug: 158290206
Test: mm
Change-Id: I0c4a491b785134e4ac1d5572e5ff94b8699dc0bc
diff --git a/src/args.rs b/src/args.rs
new file mode 100644
index 0000000..72d97e9
--- /dev/null
+++ b/src/args.rs
@@ -0,0 +1,36 @@
+use proc_macro2::Span;
+use syn::parse::{Error, Parse, ParseStream, Result};
+use syn::Token;
+
+#[derive(Copy, Clone)]
+pub struct Args {
+ pub local: bool,
+}
+
+mod kw {
+ syn::custom_keyword!(Send);
+}
+
+impl Parse for Args {
+ fn parse(input: ParseStream) -> Result<Self> {
+ match try_parse(input) {
+ Ok(args) if input.is_empty() => Ok(args),
+ _ => Err(error()),
+ }
+ }
+}
+
+fn try_parse(input: ParseStream) -> Result<Args> {
+ if input.peek(Token![?]) {
+ input.parse::<Token![?]>()?;
+ input.parse::<kw::Send>()?;
+ Ok(Args { local: true })
+ } else {
+ Ok(Args { local: false })
+ }
+}
+
+fn error() -> Error {
+ let msg = "expected #[async_trait] or #[async_trait(?Send)]";
+ Error::new(Span::call_site(), msg)
+}
