Messages in this thread Patch in this message | | | Date | Tue, 23 May 2023 17:04:05 +0100 | From | Gary Guo <> | Subject | Re: [PATCH 2/4] rust: macros: refactor generics parsing of `#[pin_data]` into its own function |
| |
On Mon, 24 Apr 2023 08:11:38 +0000 Benno Lossin <benno.lossin@proton.me> wrote:
> Other macros might also want to parse generics. Additionally this makes > the code easier to read, as the next commit will introduce more code in > `#[pin_data]`. Also add more comments to explain how parsing generics > work. > > Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
> --- > rust/macros/helpers.rs | 86 ++++++++++++++++++++++++++++++++++++++++- > rust/macros/pin_data.rs | 70 +++++---------------------------- > 2 files changed, 94 insertions(+), 62 deletions(-) > > diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs > index b2bdd4d8c958..afb0f2e3a36a 100644 > --- a/rust/macros/helpers.rs > +++ b/rust/macros/helpers.rs > @@ -1,6 +1,6 @@ > // SPDX-License-Identifier: GPL-2.0 > > -use proc_macro::{token_stream, Group, TokenTree}; > +use proc_macro::{token_stream, Group, Punct, Spacing, TokenStream, TokenTree}; > > pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> { > if let Some(TokenTree::Ident(ident)) = it.next() { > @@ -69,3 +69,87 @@ pub(crate) fn expect_end(it: &mut token_stream::IntoIter) { > panic!("Expected end"); > } > } > + > +pub(crate) struct Generics { > + pub(crate) impl_generics: Vec<TokenTree>, > + pub(crate) ty_generics: Vec<TokenTree>, > +} > + > +/// Parses the given `TokenStream` into `Generics` and the rest. > +/// > +/// The generics are not present in the rest, but a where clause might remain. > +pub(crate) fn parse_generics(input: TokenStream) -> (Generics, Vec<TokenTree>) { > + // `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 `where` token and definition. > + 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 { > + // This is inside of the generics and part of some bound. > + impl_generics.push(tt); > + } > + nesting += 1; > + } > + TokenTree::Punct(p) if p.as_char() == '>' => { > + // This is a parsing error, so we just end it here. > + if nesting == 0 { > + break; > + } else { > + nesting -= 1; > + if nesting >= 1 { > + // We are still inside of the generics and part of some bound. > + impl_generics.push(tt); > + } > + if nesting == 0 { > + break; > + } > + } > + } > + tt => { > + if nesting == 1 { > + // Here depending on the token, it might be a generic variable name. > + match &tt { > + // Ignore const. > + TokenTree::Ident(i) if i.to_string() == "const" => {} > + TokenTree::Ident(_) if at_start => { > + ty_generics.push(tt.clone()); > + // We also already push the `,` token, this makes it easier to append > + // generics. > + ty_generics.push(TokenTree::Punct(Punct::new(',', Spacing::Alone))); > + at_start = false; > + } > + TokenTree::Punct(p) if p.as_char() == ',' => at_start = true, > + // Lifetimes begin with `'`. > + 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 { > + // If we haven't entered the generics yet, we still want to keep these tokens. > + rest.push(tt); > + } > + } > + } > + } > + rest.extend(toks); > + ( > + Generics { > + impl_generics, > + ty_generics, > + }, > + rest, > + ) > +} > diff --git a/rust/macros/pin_data.rs b/rust/macros/pin_data.rs > index 954149d77181..c593b05d9e8c 100644 > --- a/rust/macros/pin_data.rs > +++ b/rust/macros/pin_data.rs > @@ -1,71 +1,19 @@ > // SPDX-License-Identifier: Apache-2.0 OR MIT > > -use proc_macro::{Punct, Spacing, TokenStream, TokenTree}; > +use crate::helpers::{parse_generics, Generics}; > +use proc_macro::TokenStream; > > 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); > + let ( > + Generics { > + impl_generics, > + ty_generics, > + }, > + mut rest, > + ) = parse_generics(input); > // This should be the body of the struct `{...}`. > let last = rest.pop(); > quote!(::kernel::__pin_data! { > -- > 2.40.0 > >
| |