linux/rust/macros/quote.rs
Benno Lossin 071cedc84e rust: add derive macro for Zeroable
Add a derive proc-macro for the `Zeroable` trait. The macro supports
structs where every field implements the `Zeroable` trait. This way
`unsafe` implementations can be avoided.

The macro is split into two parts:
- a proc-macro to parse generics into impl and ty generics,
- a declarative macro that expands to the impl block.

Suggested-by: Asahi Lina <lina@asahilina.net>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230814084602.25699-4-benno.lossin@proton.me
[ Added `ignore` to the `lib.rs` example and cleaned trivial nit. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-21 14:31:48 +02:00

158 lines
5.8 KiB
Rust

// SPDX-License-Identifier: Apache-2.0 OR MIT
use proc_macro::{TokenStream, TokenTree};
pub(crate) trait ToTokens {
fn to_tokens(&self, tokens: &mut TokenStream);
}
impl<T: ToTokens> ToTokens for Option<T> {
fn to_tokens(&self, tokens: &mut TokenStream) {
if let Some(v) = self {
v.to_tokens(tokens);
}
}
}
impl ToTokens for proc_macro::Group {
fn to_tokens(&self, tokens: &mut TokenStream) {
tokens.extend([TokenTree::from(self.clone())]);
}
}
impl ToTokens for TokenTree {
fn to_tokens(&self, tokens: &mut TokenStream) {
tokens.extend([self.clone()]);
}
}
impl ToTokens for TokenStream {
fn to_tokens(&self, tokens: &mut TokenStream) {
tokens.extend(self.clone());
}
}
/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with
/// the given span.
///
/// This is a similar to the
/// [`quote_spanned!`](https://docs.rs/quote/latest/quote/macro.quote_spanned.html) macro from the
/// `quote` crate but provides only just enough functionality needed by the current `macros` crate.
macro_rules! quote_spanned {
($span:expr => $($tt:tt)*) => {{
let mut tokens;
#[allow(clippy::vec_init_then_push)]
{
tokens = ::std::vec::Vec::new();
let span = $span;
quote_spanned!(@proc tokens span $($tt)*);
}
::proc_macro::TokenStream::from_iter(tokens)
}};
(@proc $v:ident $span:ident) => {};
(@proc $v:ident $span:ident #$id:ident $($tt:tt)*) => {
let mut ts = ::proc_macro::TokenStream::new();
$crate::quote::ToTokens::to_tokens(&$id, &mut ts);
$v.extend(ts);
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => {
for token in $id {
let mut ts = ::proc_macro::TokenStream::new();
$crate::quote::ToTokens::to_tokens(&token, &mut ts);
$v.extend(ts);
}
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident ( $($inner:tt)* ) $($tt:tt)*) => {
let mut tokens = ::std::vec::Vec::new();
quote_spanned!(@proc tokens $span $($inner)*);
$v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
::proc_macro::Delimiter::Parenthesis,
::proc_macro::TokenStream::from_iter(tokens)
)));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => {
let mut tokens = ::std::vec::Vec::new();
quote_spanned!(@proc tokens $span $($inner)*);
$v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
::proc_macro::Delimiter::Bracket,
::proc_macro::TokenStream::from_iter(tokens)
)));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => {
let mut tokens = ::std::vec::Vec::new();
quote_spanned!(@proc tokens $span $($inner)*);
$v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
::proc_macro::Delimiter::Brace,
::proc_macro::TokenStream::from_iter(tokens)
)));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident :: $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new(':', ::proc_macro::Spacing::Joint)
));
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident : $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident , $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new(',', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident @ $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new('@', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident ! $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new('!', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident ; $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new(';', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident + $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Punct(
::proc_macro::Punct::new('+', ::proc_macro::Spacing::Alone)
));
quote_spanned!(@proc $v $span $($tt)*);
};
(@proc $v:ident $span:ident $id:ident $($tt:tt)*) => {
$v.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new(stringify!($id), $span)));
quote_spanned!(@proc $v $span $($tt)*);
};
}
/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with
/// mixed site span ([`Span::mixed_site()`]).
///
/// This is a similar to the [`quote!`](https://docs.rs/quote/latest/quote/macro.quote.html) macro
/// from the `quote` crate but provides only just enough functionality needed by the current
/// `macros` crate.
///
/// [`Span::mixed_site()`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.mixed_site
macro_rules! quote {
($($tt:tt)*) => {
quote_spanned!(::proc_macro::Span::mixed_site() => $($tt)*)
}
}