diff options
Diffstat (limited to 'rust/macros')
| -rw-r--r-- | rust/macros/helpers.rs | 86 | ||||
| -rw-r--r-- | rust/macros/pin_data.rs | 168 | ||||
| -rw-r--r-- | rust/macros/quote.rs | 14 |
3 files changed, 201 insertions, 67 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..6d58cfda9872 100644 --- a/rust/macros/pin_data.rs +++ b/rust/macros/pin_data.rs @@ -1,79 +1,127 @@ // SPDX-License-Identifier: Apache-2.0 OR MIT -use proc_macro::{Punct, Spacing, TokenStream, TokenTree}; +use crate::helpers::{parse_generics, Generics}; +use proc_macro::{Group, Punct, Spacing, TokenStream, TokenTree}; 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; - } + let ( + Generics { + impl_generics, + ty_generics, + }, + rest, + ) = parse_generics(input); + // The struct definition might contain the `Self` type. Since `__pin_data!` will define a new + // type with the same generics and bounds, this poses a problem, since `Self` will refer to the + // new type as opposed to this struct definition. Therefore we have to replace `Self` with the + // concrete name. + + // Errors that occur when replacing `Self` with `struct_name`. + let mut errs = TokenStream::new(); + // The name of the struct with ty_generics. + let struct_name = rest + .iter() + .skip_while(|tt| !matches!(tt, TokenTree::Ident(i) if i.to_string() == "struct")) + .nth(1) + .and_then(|tt| match tt { + TokenTree::Ident(_) => { + let tt = tt.clone(); + let mut res = vec![tt]; + if !ty_generics.is_empty() { + // We add this, so it is maximally compatible with e.g. `Self::CONST` which + // will be replaced by `StructName::<$generics>::CONST`. + res.push(TokenTree::Punct(Punct::new(':', Spacing::Joint))); + res.push(TokenTree::Punct(Punct::new(':', Spacing::Alone))); + res.push(TokenTree::Punct(Punct::new('<', Spacing::Alone))); + res.extend(ty_generics.iter().cloned()); + res.push(TokenTree::Punct(Punct::new('>', Spacing::Alone))); } + Some(res) } - 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); - } + _ => None, + }) + .unwrap_or_else(|| { + // If we did not find the name of the struct then we will use `Self` as the replacement + // and add a compile error to ensure it does not compile. + errs.extend( + "::core::compile_error!(\"Could not locate type name.\");" + .parse::<TokenStream>() + .unwrap(), + ); + "Self".parse::<TokenStream>().unwrap().into_iter().collect() + }); + let impl_generics = impl_generics + .into_iter() + .flat_map(|tt| replace_self_and_deny_type_defs(&struct_name, tt, &mut errs)) + .collect::<Vec<_>>(); + let mut rest = rest + .into_iter() + .flat_map(|tt| { + // We ignore top level `struct` tokens, since they would emit a compile error. + if matches!(&tt, TokenTree::Ident(i) if i.to_string() == "struct") { + vec![tt] + } else { + replace_self_and_deny_type_defs(&struct_name, tt, &mut errs) } - } - } - rest.extend(toks); + }) + .collect::<Vec<_>>(); // This should be the body of the struct `{...}`. let last = rest.pop(); - quote!(::kernel::__pin_data! { + let mut quoted = quote!(::kernel::__pin_data! { parse_input: @args(#args), @sig(#(#rest)*), @impl_generics(#(#impl_generics)*), @ty_generics(#(#ty_generics)*), @body(#last), - }) + }); + quoted.extend(errs); + quoted +} + +/// Replaces `Self` with `struct_name` and errors on `enum`, `trait`, `struct` `union` and `impl` +/// keywords. +/// +/// The error is appended to `errs` to allow normal parsing to continue. +fn replace_self_and_deny_type_defs( + struct_name: &Vec<TokenTree>, + tt: TokenTree, + errs: &mut TokenStream, +) -> Vec<TokenTree> { + match tt { + TokenTree::Ident(ref i) + if i.to_string() == "enum" + || i.to_string() == "trait" + || i.to_string() == "struct" + || i.to_string() == "union" + || i.to_string() == "impl" => + { + errs.extend( + format!( + "::core::compile_error!(\"Cannot use `{i}` inside of struct definition with \ + `#[pin_data]`.\");" + ) + .parse::<TokenStream>() + .unwrap() + .into_iter() + .map(|mut tok| { + tok.set_span(tt.span()); + tok + }), + ); + vec![tt] + } + TokenTree::Ident(i) if i.to_string() == "Self" => struct_name.clone(), + TokenTree::Literal(_) | TokenTree::Punct(_) | TokenTree::Ident(_) => vec![tt], + TokenTree::Group(g) => vec![TokenTree::Group(Group::new( + g.delimiter(), + g.stream() + .into_iter() + .flat_map(|tt| replace_self_and_deny_type_defs(struct_name, tt, errs)) + .collect(), + ))], + } } diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs index c8e08b3c1e4c..dddbb4e6f4cb 100644 --- a/rust/macros/quote.rs +++ b/rust/macros/quote.rs @@ -39,12 +39,14 @@ impl ToTokens for TokenStream { /// [`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)*) => { - #[allow(clippy::vec_init_then_push)] - { - let mut tokens = ::std::vec::Vec::new(); - let span = $span; - quote_spanned!(@proc tokens span $($tt)*); + ($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) => {}; |