blob: 6d58cfda9872e6231523d1e8df5cff8ea73678de [file] [log] [blame]
Benno Lossinfc6c6ba2023-04-08 12:25:51 +00001// SPDX-License-Identifier: Apache-2.0 OR MIT
2
Benno Lossine957b9c2023-04-24 08:11:38 +00003use crate::helpers::{parse_generics, Generics};
Benno Lossin52b7bb42023-04-24 08:11:43 +00004use proc_macro::{Group, Punct, Spacing, TokenStream, TokenTree};
Benno Lossinfc6c6ba2023-04-08 12:25:51 +00005
6pub(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!`.
Benno Lossinfc6c6ba2023-04-08 12:25:51 +00009
Benno Lossine957b9c2023-04-24 08:11:38 +000010 let (
11 Generics {
12 impl_generics,
13 ty_generics,
14 },
Benno Lossin52b7bb42023-04-24 08:11:43 +000015 rest,
Benno Lossine957b9c2023-04-24 08:11:38 +000016 ) = parse_generics(input);
Benno Lossin52b7bb42023-04-24 08:11:43 +000017 // The struct definition might contain the `Self` type. Since `__pin_data!` will define a new
18 // type with the same generics and bounds, this poses a problem, since `Self` will refer to the
19 // new type as opposed to this struct definition. Therefore we have to replace `Self` with the
20 // concrete name.
21
22 // Errors that occur when replacing `Self` with `struct_name`.
23 let mut errs = TokenStream::new();
24 // The name of the struct with ty_generics.
25 let struct_name = rest
26 .iter()
27 .skip_while(|tt| !matches!(tt, TokenTree::Ident(i) if i.to_string() == "struct"))
28 .nth(1)
29 .and_then(|tt| match tt {
30 TokenTree::Ident(_) => {
31 let tt = tt.clone();
32 let mut res = vec![tt];
33 if !ty_generics.is_empty() {
34 // We add this, so it is maximally compatible with e.g. `Self::CONST` which
35 // will be replaced by `StructName::<$generics>::CONST`.
36 res.push(TokenTree::Punct(Punct::new(':', Spacing::Joint)));
37 res.push(TokenTree::Punct(Punct::new(':', Spacing::Alone)));
38 res.push(TokenTree::Punct(Punct::new('<', Spacing::Alone)));
39 res.extend(ty_generics.iter().cloned());
40 res.push(TokenTree::Punct(Punct::new('>', Spacing::Alone)));
41 }
42 Some(res)
43 }
44 _ => None,
45 })
46 .unwrap_or_else(|| {
47 // If we did not find the name of the struct then we will use `Self` as the replacement
48 // and add a compile error to ensure it does not compile.
49 errs.extend(
50 "::core::compile_error!(\"Could not locate type name.\");"
51 .parse::<TokenStream>()
52 .unwrap(),
53 );
54 "Self".parse::<TokenStream>().unwrap().into_iter().collect()
55 });
56 let impl_generics = impl_generics
57 .into_iter()
58 .flat_map(|tt| replace_self_and_deny_type_defs(&struct_name, tt, &mut errs))
59 .collect::<Vec<_>>();
60 let mut rest = rest
61 .into_iter()
62 .flat_map(|tt| {
63 // We ignore top level `struct` tokens, since they would emit a compile error.
64 if matches!(&tt, TokenTree::Ident(i) if i.to_string() == "struct") {
65 vec![tt]
66 } else {
67 replace_self_and_deny_type_defs(&struct_name, tt, &mut errs)
68 }
69 })
70 .collect::<Vec<_>>();
Benno Lossinfc6c6ba2023-04-08 12:25:51 +000071 // This should be the body of the struct `{...}`.
72 let last = rest.pop();
Benno Lossin52b7bb42023-04-24 08:11:43 +000073 let mut quoted = quote!(::kernel::__pin_data! {
Benno Lossinfc6c6ba2023-04-08 12:25:51 +000074 parse_input:
75 @args(#args),
76 @sig(#(#rest)*),
77 @impl_generics(#(#impl_generics)*),
78 @ty_generics(#(#ty_generics)*),
79 @body(#last),
Benno Lossin52b7bb42023-04-24 08:11:43 +000080 });
81 quoted.extend(errs);
82 quoted
83}
84
85/// Replaces `Self` with `struct_name` and errors on `enum`, `trait`, `struct` `union` and `impl`
86/// keywords.
87///
88/// The error is appended to `errs` to allow normal parsing to continue.
89fn replace_self_and_deny_type_defs(
90 struct_name: &Vec<TokenTree>,
91 tt: TokenTree,
92 errs: &mut TokenStream,
93) -> Vec<TokenTree> {
94 match tt {
95 TokenTree::Ident(ref i)
96 if i.to_string() == "enum"
97 || i.to_string() == "trait"
98 || i.to_string() == "struct"
99 || i.to_string() == "union"
100 || i.to_string() == "impl" =>
101 {
102 errs.extend(
103 format!(
104 "::core::compile_error!(\"Cannot use `{i}` inside of struct definition with \
105 `#[pin_data]`.\");"
106 )
107 .parse::<TokenStream>()
108 .unwrap()
109 .into_iter()
110 .map(|mut tok| {
111 tok.set_span(tt.span());
112 tok
113 }),
114 );
115 vec![tt]
116 }
117 TokenTree::Ident(i) if i.to_string() == "Self" => struct_name.clone(),
118 TokenTree::Literal(_) | TokenTree::Punct(_) | TokenTree::Ident(_) => vec![tt],
119 TokenTree::Group(g) => vec![TokenTree::Group(Group::new(
120 g.delimiter(),
121 g.stream()
122 .into_iter()
123 .flat_map(|tt| replace_self_and_deny_type_defs(struct_name, tt, errs))
124 .collect(),
125 ))],
126 }
Benno Lossinfc6c6ba2023-04-08 12:25:51 +0000127}