1 // SPDX-License-Identifier: Apache-2.0 OR MIT
2
3 use crate::helpers::{parse_generics, Generics};
4 use proc_macro::{Group, Punct, Spacing, TokenStream, TokenTree};
5
pin_data(args: TokenStream, input: TokenStream) -> TokenStream6 pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
7 // This proc-macro only does some pre-parsing and then delegates the actual parsing to
8 // `kernel::__pin_data!`.
9
10 let (
11 Generics {
12 impl_generics,
13 decl_generics,
14 ty_generics,
15 },
16 rest,
17 ) = parse_generics(input);
18 // The struct definition might contain the `Self` type. Since `__pin_data!` will define a new
19 // type with the same generics and bounds, this poses a problem, since `Self` will refer to the
20 // new type as opposed to this struct definition. Therefore we have to replace `Self` with the
21 // concrete name.
22
23 // Errors that occur when replacing `Self` with `struct_name`.
24 let mut errs = TokenStream::new();
25 // The name of the struct with ty_generics.
26 let struct_name = rest
27 .iter()
28 .skip_while(|tt| !matches!(tt, TokenTree::Ident(i) if i.to_string() == "struct"))
29 .nth(1)
30 .and_then(|tt| match tt {
31 TokenTree::Ident(_) => {
32 let tt = tt.clone();
33 let mut res = vec![tt];
34 if !ty_generics.is_empty() {
35 // We add this, so it is maximally compatible with e.g. `Self::CONST` which
36 // will be replaced by `StructName::<$generics>::CONST`.
37 res.push(TokenTree::Punct(Punct::new(':', Spacing::Joint)));
38 res.push(TokenTree::Punct(Punct::new(':', Spacing::Alone)));
39 res.push(TokenTree::Punct(Punct::new('<', Spacing::Alone)));
40 res.extend(ty_generics.iter().cloned());
41 res.push(TokenTree::Punct(Punct::new('>', Spacing::Alone)));
42 }
43 Some(res)
44 }
45 _ => None,
46 })
47 .unwrap_or_else(|| {
48 // If we did not find the name of the struct then we will use `Self` as the replacement
49 // and add a compile error to ensure it does not compile.
50 errs.extend(
51 "::core::compile_error!(\"Could not locate type name.\");"
52 .parse::<TokenStream>()
53 .unwrap(),
54 );
55 "Self".parse::<TokenStream>().unwrap().into_iter().collect()
56 });
57 let impl_generics = impl_generics
58 .into_iter()
59 .flat_map(|tt| replace_self_and_deny_type_defs(&struct_name, tt, &mut errs))
60 .collect::<Vec<_>>();
61 let mut rest = rest
62 .into_iter()
63 .flat_map(|tt| {
64 // We ignore top level `struct` tokens, since they would emit a compile error.
65 if matches!(&tt, TokenTree::Ident(i) if i.to_string() == "struct") {
66 vec![tt]
67 } else {
68 replace_self_and_deny_type_defs(&struct_name, tt, &mut errs)
69 }
70 })
71 .collect::<Vec<_>>();
72 // This should be the body of the struct `{...}`.
73 let last = rest.pop();
74 let mut quoted = quote!(::kernel::__pin_data! {
75 parse_input:
76 @args(#args),
77 @sig(#(#rest)*),
78 @impl_generics(#(#impl_generics)*),
79 @ty_generics(#(#ty_generics)*),
80 @decl_generics(#(#decl_generics)*),
81 @body(#last),
82 });
83 quoted.extend(errs);
84 quoted
85 }
86
87 /// Replaces `Self` with `struct_name` and errors on `enum`, `trait`, `struct` `union` and `impl`
88 /// keywords.
89 ///
90 /// The error is appended to `errs` to allow normal parsing to continue.
replace_self_and_deny_type_defs( struct_name: &Vec<TokenTree>, tt: TokenTree, errs: &mut TokenStream, ) -> Vec<TokenTree>91 fn replace_self_and_deny_type_defs(
92 struct_name: &Vec<TokenTree>,
93 tt: TokenTree,
94 errs: &mut TokenStream,
95 ) -> Vec<TokenTree> {
96 match tt {
97 TokenTree::Ident(ref i)
98 if i.to_string() == "enum"
99 || i.to_string() == "trait"
100 || i.to_string() == "struct"
101 || i.to_string() == "union"
102 || i.to_string() == "impl" =>
103 {
104 errs.extend(
105 format!(
106 "::core::compile_error!(\"Cannot use `{i}` inside of struct definition with \
107 `#[pin_data]`.\");"
108 )
109 .parse::<TokenStream>()
110 .unwrap()
111 .into_iter()
112 .map(|mut tok| {
113 tok.set_span(tt.span());
114 tok
115 }),
116 );
117 vec![tt]
118 }
119 TokenTree::Ident(i) if i.to_string() == "Self" => struct_name.clone(),
120 TokenTree::Literal(_) | TokenTree::Punct(_) | TokenTree::Ident(_) => vec![tt],
121 TokenTree::Group(g) => vec![TokenTree::Group(Group::new(
122 g.delimiter(),
123 g.stream()
124 .into_iter()
125 .flat_map(|tt| replace_self_and_deny_type_defs(struct_name, tt, errs))
126 .collect(),
127 ))],
128 }
129 }
130