1 files changed, 182 insertions, 0 deletions
diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs
new file mode 100644
index 000000000000..ddfc21577539
--- /dev/null
+++ b/rust/macros/quote.rs
@@ -0,0 +1,182 @@
+// 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 proc_macro::Ident {
+    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 = ::proc_macro::TokenStream::new();
+        {
+            #[allow(unused_variables)]
+            let span = $span;
+            quote_spanned!(@proc tokens span $($tt)*);
+        }
+        tokens
+    }};
+    (@proc $v:ident $span:ident) => {};
+    (@proc $v:ident $span:ident #$id:ident $($tt:tt)*) => {
+        $crate::quote::ToTokens::to_tokens(&$id, &mut $v);
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => {
+        for token in $id {
+            $crate::quote::ToTokens::to_tokens(&token, &mut $v);
+        }
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident ( $($inner:tt)* ) $($tt:tt)*) => {
+        #[allow(unused_mut)]
+        let mut tokens = ::proc_macro::TokenStream::new();
+        quote_spanned!(@proc tokens $span $($inner)*);
+        $v.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+            ::proc_macro::Delimiter::Parenthesis,
+            tokens,
+        ))]);
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => {
+        let mut tokens = ::proc_macro::TokenStream::new();
+        quote_spanned!(@proc tokens $span $($inner)*);
+        $v.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+            ::proc_macro::Delimiter::Bracket,
+            tokens,
+        ))]);
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => {
+        let mut tokens = ::proc_macro::TokenStream::new();
+        quote_spanned!(@proc tokens $span $($inner)*);
+        $v.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+            ::proc_macro::Delimiter::Brace,
+            tokens,
+        ))]);
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident :: $($tt:tt)*) => {
+        $v.extend([::proc_macro::Spacing::Joint, ::proc_macro::Spacing::Alone].map(|spacing| {
+            ::proc_macro::TokenTree::Punct(::proc_macro::Punct::new(':', spacing))
+        }));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident : $($tt:tt)*) => {
+        $v.extend([::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.extend([::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.extend([::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.extend([::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.extend([::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.extend([::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.extend([::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.extend([::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.extend([::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.extend([::proc_macro::TokenTree::Ident(
+            ::proc_macro::Ident::new("_", $span),
+        )]);
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident $id:ident $($tt:tt)*) => {
+        $v.extend([::proc_macro::TokenTree::Ident(
+            ::proc_macro::Ident::new(stringify!($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)*)
+    }
+}