diff mbox series

[v11,1/5] rust: macros: reduce collections in `quote!` macro

Message ID 20250530-cstr-core-v11-1-cd9c0cbcb902@gmail.com
State New
Headers show
Series rust: replace kernel::str::CStr w/ core::ffi::CStr | expand

Commit Message

Tamir Duberstein May 30, 2025, 12:27 p.m. UTC 
Remove a handful of unncessary intermediate vectors and token streams;
mainly the top-level stream can be directly extended with the notable
exception of groups.

Remove an unnecessary `#[allow(dead_code)]` added in commit dbd5058ba60c
("rust: make pin-init its own crate").

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/macros/quote.rs | 104 ++++++++++++++++++++++++---------------------------
 1 file changed, 49 insertions(+), 55 deletions(-)

Comments

Benno Lossin June 1, 2025, 4:24 p.m. UTC | #1 
On Fri May 30, 2025 at 2:27 PM CEST, Tamir Duberstein wrote:
> Remove a handful of unncessary intermediate vectors and token streams;
> mainly the top-level stream can be directly extended with the notable
> exception of groups.

What's the motivation for this? I wouldn't spend much effort on this
file, as it'll go away when we add the `quote` crate.

---
Cheers,
Benno

> Remove an unnecessary `#[allow(dead_code)]` added in commit dbd5058ba60c
> ("rust: make pin-init its own crate").
>
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> ---
>  rust/macros/quote.rs | 104 ++++++++++++++++++++++++---------------------------
>  1 file changed, 49 insertions(+), 55 deletions(-)
Tamir Duberstein June 1, 2025, 7:42 p.m. UTC | #2 
On Sun, Jun 1, 2025 at 12:24 PM Benno Lossin <lossin@kernel.org> wrote:
>
> On Fri May 30, 2025 at 2:27 PM CEST, Tamir Duberstein wrote:
> > Remove a handful of unncessary intermediate vectors and token streams;
> > mainly the top-level stream can be directly extended with the notable
> > exception of groups.
>
> What's the motivation for this?

I was squinting at the macro to understand how it worked and spotted
these oddities.

> I wouldn't spend much effort on this file, as it'll go away when we add the `quote` crate.

Eh, this seems to be in the "I'll believe it when I see it" category.
diff mbox series

Patch

diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs
index 92cacc4067c9..acc140c18653 100644
--- a/rust/macros/quote.rs
+++ b/rust/macros/quote.rs
@@ -2,7 +2,6 @@ 
 
 use proc_macro::{TokenStream, TokenTree};
 
-#[allow(dead_code)]
 pub(crate) trait ToTokens {
     fn to_tokens(&self, tokens: &mut TokenStream);
 }
@@ -47,121 +46,116 @@  fn to_tokens(&self, tokens: &mut TokenStream) {
 /// `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: ::std::vec::Vec<::proc_macro::TokenTree>;
-        #[allow(clippy::vec_init_then_push)]
+        let mut tokens = ::proc_macro::TokenStream::new();
         {
-            tokens = ::std::vec::Vec::new();
             let span = $span;
             quote_spanned!(@proc tokens span $($tt)*);
         }
-        ::proc_macro::TokenStream::from_iter(tokens)
+        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);
+        $crate::quote::ToTokens::to_tokens(&$id, &mut $v);
         quote_spanned!(@proc $v $span $($tt)*);
     };
     (@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => {
         for token in $id {
-            let mut ts = ::proc_macro::TokenStream::new();
-            $crate::quote::ToTokens::to_tokens(&token, &mut ts);
-            $v.extend(ts);
+            $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 = ::std::vec::Vec::<::proc_macro::TokenTree>::new();
+        let mut tokens = ::proc_macro::TokenStream::new();
         quote_spanned!(@proc tokens $span $($inner)*);
-        $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+        $v.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
             ::proc_macro::Delimiter::Parenthesis,
-            ::proc_macro::TokenStream::from_iter(tokens)
-        )));
+            tokens,
+        ))]);
         quote_spanned!(@proc $v $span $($tt)*);
     };
     (@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => {
-        let mut tokens = ::std::vec::Vec::new();
+        let mut tokens = ::proc_macro::TokenStream::new();
         quote_spanned!(@proc tokens $span $($inner)*);
-        $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+        $v.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
             ::proc_macro::Delimiter::Bracket,
-            ::proc_macro::TokenStream::from_iter(tokens)
-        )));
+            tokens,
+        ))]);
         quote_spanned!(@proc $v $span $($tt)*);
     };
     (@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => {
-        let mut tokens = ::std::vec::Vec::new();
+        let mut tokens = ::proc_macro::TokenStream::new();
         quote_spanned!(@proc tokens $span $($inner)*);
-        $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+        $v.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
             ::proc_macro::Delimiter::Brace,
-            ::proc_macro::TokenStream::from_iter(tokens)
-        )));
+            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)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new(',', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new('@', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new('!', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new(';', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new('+', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new('=', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Punct(
-                ::proc_macro::Punct::new('#', ::proc_macro::Spacing::Alone)
-        ));
+        $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.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new("_", $span)));
+        $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)*) => {
-        $v.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new(stringify!($id), $span)));
+        $v.extend([::proc_macro::TokenTree::Ident(
+            ::proc_macro::Ident::new(stringify!($id), $span),
+        )]);
         quote_spanned!(@proc $v $span $($tt)*);
     };
 }