Commit 70a21e54 authored by Gary Guo's avatar Gary Guo Committed by Miguel Ojeda
Browse files

rust: macros: add `quote!` macro 



Add the `quote!` macro for creating `TokenStream`s directly via the
given Rust tokens. It also supports repetitions using iterators.

It will be used by the pin-init API proc-macros to generate code.

Signed-off-by: default avatarGary Guo <gary@garyguo.net>
Signed-off-by: default avatarBenno Lossin <benno.lossin@proton.me>
Reviewed-by: default avatarAndreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-3-y86-dev@protonmail.com


Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent 2d19d369

rust/macros/lib.rs

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@@ -2,6 +2,8 @@ 


//! Crate for all kernel procedural macros.



#[macro_use]

mod quote;

mod concat_idents;

mod helpers;

mod module;

rust/macros/quote.rs

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// 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.

#[allow(unused_macros)]

macro_rules! quote_spanned {

    ($span:expr => $($tt:tt)*) => {

    #[allow(clippy::vec_init_then_push)]

    {

        let mut 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 $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

#[allow(unused_macros)]

macro_rules! quote {

    ($($tt:tt)*) => {

        quote_spanned!(::proc_macro::Span::mixed_site() => $($tt)*)

    }

}