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-rw-r--r--rust/macros/pin_data.rs79
1 files changed, 79 insertions, 0 deletions
diff --git a/rust/macros/pin_data.rs b/rust/macros/pin_data.rs
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+++ b/rust/macros/pin_data.rs
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+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use proc_macro::{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!`.
+ //
+ // In here we only collect the generics, since parsing them in declarative macros is very
+ // elaborate. We also do not need to analyse their structure, we only need to collect them.
+
+ // `impl_generics`, the declared generics with their bounds.
+ let mut impl_generics = vec![];
+ // Only the names of the generics, without any bounds.
+ let mut ty_generics = vec![];
+ // Tokens not related to the generics e.g. the `impl` token.
+ let mut rest = vec![];
+ // The current level of `<`.
+ let mut nesting = 0;
+ let mut toks = input.into_iter();
+ // If we are at the beginning of a generic parameter.
+ let mut at_start = true;
+ for tt in &mut toks {
+ match tt.clone() {
+ TokenTree::Punct(p) if p.as_char() == '<' => {
+ if nesting >= 1 {
+ impl_generics.push(tt);
+ }
+ nesting += 1;
+ }
+ TokenTree::Punct(p) if p.as_char() == '>' => {
+ if nesting == 0 {
+ break;
+ } else {
+ nesting -= 1;
+ if nesting >= 1 {
+ impl_generics.push(tt);
+ }
+ if nesting == 0 {
+ break;
+ }
+ }
+ }
+ tt => {
+ if nesting == 1 {
+ match &tt {
+ TokenTree::Ident(i) if i.to_string() == "const" => {}
+ TokenTree::Ident(_) if at_start => {
+ ty_generics.push(tt.clone());
+ ty_generics.push(TokenTree::Punct(Punct::new(',', Spacing::Alone)));
+ at_start = false;
+ }
+ TokenTree::Punct(p) if p.as_char() == ',' => at_start = true,
+ TokenTree::Punct(p) if p.as_char() == '\'' && at_start => {
+ ty_generics.push(tt.clone());
+ }
+ _ => {}
+ }
+ }
+ if nesting >= 1 {
+ impl_generics.push(tt);
+ } else if nesting == 0 {
+ rest.push(tt);
+ }
+ }
+ }
+ }
+ rest.extend(toks);
+ // This should be the body of the struct `{...}`.
+ let last = rest.pop();
+ quote!(::kernel::__pin_data! {
+ parse_input:
+ @args(#args),
+ @sig(#(#rest)*),
+ @impl_generics(#(#impl_generics)*),
+ @ty_generics(#(#ty_generics)*),
+ @body(#last),
+ })
+}