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// SPDX-License-Identifier: Apache-2.0 OR MIT
use crate::helpers::{parse_generics, Generics};
use proc_macro::{Group, Punct, Spacing, TokenStream, TokenTree};
pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
// This proc-macro only does some pre-parsing and then delegates the actual parsing to
// `kernel::__pin_data!`.
let (
Generics {
impl_generics,
ty_generics,
},
rest,
) = parse_generics(input);
// The struct definition might contain the `Self` type. Since `__pin_data!` will define a new
// type with the same generics and bounds, this poses a problem, since `Self` will refer to the
// new type as opposed to this struct definition. Therefore we have to replace `Self` with the
// concrete name.
// Errors that occur when replacing `Self` with `struct_name`.
let mut errs = TokenStream::new();
// The name of the struct with ty_generics.
let struct_name = rest
.iter()
.skip_while(|tt| !matches!(tt, TokenTree::Ident(i) if i.to_string() == "struct"))
.nth(1)
.and_then(|tt| match tt {
TokenTree::Ident(_) => {
let tt = tt.clone();
let mut res = vec![tt];
if !ty_generics.is_empty() {
// We add this, so it is maximally compatible with e.g. `Self::CONST` which
// will be replaced by `StructName::<$generics>::CONST`.
res.push(TokenTree::Punct(Punct::new(':', Spacing::Joint)));
res.push(TokenTree::Punct(Punct::new(':', Spacing::Alone)));
res.push(TokenTree::Punct(Punct::new('<', Spacing::Alone)));
res.extend(ty_generics.iter().cloned());
res.push(TokenTree::Punct(Punct::new('>', Spacing::Alone)));
}
Some(res)
}
_ => None,
})
.unwrap_or_else(|| {
// If we did not find the name of the struct then we will use `Self` as the replacement
// and add a compile error to ensure it does not compile.
errs.extend(
"::core::compile_error!(\"Could not locate type name.\");"
.parse::<TokenStream>()
.unwrap(),
);
"Self".parse::<TokenStream>().unwrap().into_iter().collect()
});
let impl_generics = impl_generics
.into_iter()
.flat_map(|tt| replace_self_and_deny_type_defs(&struct_name, tt, &mut errs))
.collect::<Vec<_>>();
let mut rest = rest
.into_iter()
.flat_map(|tt| {
// We ignore top level `struct` tokens, since they would emit a compile error.
if matches!(&tt, TokenTree::Ident(i) if i.to_string() == "struct") {
vec![tt]
} else {
replace_self_and_deny_type_defs(&struct_name, tt, &mut errs)
}
})
.collect::<Vec<_>>();
// This should be the body of the struct `{...}`.
let last = rest.pop();
let mut quoted = quote!(::kernel::__pin_data! {
parse_input:
@args(#args),
@sig(#(#rest)*),
@impl_generics(#(#impl_generics)*),
@ty_generics(#(#ty_generics)*),
@body(#last),
});
quoted.extend(errs);
quoted
}
/// Replaces `Self` with `struct_name` and errors on `enum`, `trait`, `struct` `union` and `impl`
/// keywords.
///
/// The error is appended to `errs` to allow normal parsing to continue.
fn replace_self_and_deny_type_defs(
struct_name: &Vec<TokenTree>,
tt: TokenTree,
errs: &mut TokenStream,
) -> Vec<TokenTree> {
match tt {
TokenTree::Ident(ref i)
if i.to_string() == "enum"
|| i.to_string() == "trait"
|| i.to_string() == "struct"
|| i.to_string() == "union"
|| i.to_string() == "impl" =>
{
errs.extend(
format!(
"::core::compile_error!(\"Cannot use `{i}` inside of struct definition with \
`#[pin_data]`.\");"
)
.parse::<TokenStream>()
.unwrap()
.into_iter()
.map(|mut tok| {
tok.set_span(tt.span());
tok
}),
);
vec![tt]
}
TokenTree::Ident(i) if i.to_string() == "Self" => struct_name.clone(),
TokenTree::Literal(_) | TokenTree::Punct(_) | TokenTree::Ident(_) => vec![tt],
TokenTree::Group(g) => vec![TokenTree::Group(Group::new(
g.delimiter(),
g.stream()
.into_iter()
.flat_map(|tt| replace_self_and_deny_type_defs(struct_name, tt, errs))
.collect(),
))],
}
}
|
