diff options
Diffstat (limited to 'rust/macros')
| -rw-r--r-- | rust/macros/lib.rs | 97 | ||||
| -rw-r--r-- | rust/macros/paste.rs | 96 |
2 files changed, 193 insertions, 0 deletions
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 3fc74cb4ea19..b4bc44c27bd4 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -7,6 +7,7 @@ mod quote; mod concat_idents; mod helpers; mod module; +mod paste; mod pin_data; mod pinned_drop; mod vtable; @@ -246,3 +247,99 @@ pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream { pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream { pinned_drop::pinned_drop(args, input) } + +/// Paste identifiers together. +/// +/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a +/// single identifier. +/// +/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers +/// (literals, lifetimes and documentation strings are not supported). There is a difference in +/// supported modifiers as well. +/// +/// # Example +/// +/// ```ignore +/// use kernel::macro::paste; +/// +/// macro_rules! pub_no_prefix { +/// ($prefix:ident, $($newname:ident),+) => { +/// paste! { +/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ +/// } +/// }; +/// } +/// +/// pub_no_prefix!( +/// binder_driver_return_protocol_, +/// BR_OK, +/// BR_ERROR, +/// BR_TRANSACTION, +/// BR_REPLY, +/// BR_DEAD_REPLY, +/// BR_TRANSACTION_COMPLETE, +/// BR_INCREFS, +/// BR_ACQUIRE, +/// BR_RELEASE, +/// BR_DECREFS, +/// BR_NOOP, +/// BR_SPAWN_LOOPER, +/// BR_DEAD_BINDER, +/// BR_CLEAR_DEATH_NOTIFICATION_DONE, +/// BR_FAILED_REPLY +/// ); +/// +/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); +/// ``` +/// +/// # Modifiers +/// +/// For each identifier, it is possible to attach one or multiple modifiers to +/// it. +/// +/// Currently supported modifiers are: +/// * `span`: change the span of concatenated identifier to the span of the specified token. By +/// default the span of the `[< >]` group is used. +/// * `lower`: change the identifier to lower case. +/// * `upper`: change the identifier to upper case. +/// +/// ```ignore +/// use kernel::macro::paste; +/// +/// macro_rules! pub_no_prefix { +/// ($prefix:ident, $($newname:ident),+) => { +/// kernel::macros::paste! { +/// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+ +/// } +/// }; +/// } +/// +/// pub_no_prefix!( +/// binder_driver_return_protocol_, +/// BR_OK, +/// BR_ERROR, +/// BR_TRANSACTION, +/// BR_REPLY, +/// BR_DEAD_REPLY, +/// BR_TRANSACTION_COMPLETE, +/// BR_INCREFS, +/// BR_ACQUIRE, +/// BR_RELEASE, +/// BR_DECREFS, +/// BR_NOOP, +/// BR_SPAWN_LOOPER, +/// BR_DEAD_BINDER, +/// BR_CLEAR_DEATH_NOTIFICATION_DONE, +/// BR_FAILED_REPLY +/// ); +/// +/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); +/// ``` +/// +/// [`paste`]: https://docs.rs/paste/ +#[proc_macro] +pub fn paste(input: TokenStream) -> TokenStream { + let mut tokens = input.into_iter().collect(); + paste::expand(&mut tokens); + tokens.into_iter().collect() +} diff --git a/rust/macros/paste.rs b/rust/macros/paste.rs new file mode 100644 index 000000000000..385a78434224 --- /dev/null +++ b/rust/macros/paste.rs @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0 + +use proc_macro::{Delimiter, Group, Ident, Spacing, Span, TokenTree}; + +fn concat(tokens: &[TokenTree], group_span: Span) -> TokenTree { + let mut tokens = tokens.iter(); + let mut segments = Vec::new(); + let mut span = None; + loop { + match tokens.next() { + None => break, + Some(TokenTree::Literal(lit)) => segments.push((lit.to_string(), lit.span())), + Some(TokenTree::Ident(ident)) => { + let mut value = ident.to_string(); + if value.starts_with("r#") { + value.replace_range(0..2, ""); + } + segments.push((value, ident.span())); + } + Some(TokenTree::Punct(p)) if p.as_char() == ':' => { + let Some(TokenTree::Ident(ident)) = tokens.next() else { + panic!("expected identifier as modifier"); + }; + + let (mut value, sp) = segments.pop().expect("expected identifier before modifier"); + match ident.to_string().as_str() { + // Set the overall span of concatenated token as current span + "span" => { + assert!( + span.is_none(), + "span modifier should only appear at most once" + ); + span = Some(sp); + } + "lower" => value = value.to_lowercase(), + "upper" => value = value.to_uppercase(), + v => panic!("unknown modifier `{v}`"), + }; + segments.push((value, sp)); + } + _ => panic!("unexpected token in paste segments"), + }; + } + + let pasted: String = segments.into_iter().map(|x| x.0).collect(); + TokenTree::Ident(Ident::new(&pasted, span.unwrap_or(group_span))) +} + +pub(crate) fn expand(tokens: &mut Vec<TokenTree>) { + for token in tokens.iter_mut() { + if let TokenTree::Group(group) = token { + let delimiter = group.delimiter(); + let span = group.span(); + let mut stream: Vec<_> = group.stream().into_iter().collect(); + // Find groups that looks like `[< A B C D >]` + if delimiter == Delimiter::Bracket + && stream.len() >= 3 + && matches!(&stream[0], TokenTree::Punct(p) if p.as_char() == '<') + && matches!(&stream[stream.len() - 1], TokenTree::Punct(p) if p.as_char() == '>') + { + // Replace the group with concatenated token + *token = concat(&stream[1..stream.len() - 1], span); + } else { + // Recursively expand tokens inside the group + expand(&mut stream); + let mut group = Group::new(delimiter, stream.into_iter().collect()); + group.set_span(span); + *token = TokenTree::Group(group); + } + } + } + + // Path segments cannot contain invisible delimiter group, so remove them if any. + for i in (0..tokens.len().saturating_sub(3)).rev() { + // Looking for a double colon + if matches!( + (&tokens[i + 1], &tokens[i + 2]), + (TokenTree::Punct(a), TokenTree::Punct(b)) + if a.as_char() == ':' && a.spacing() == Spacing::Joint && b.as_char() == ':' + ) { + match &tokens[i + 3] { + TokenTree::Group(group) if group.delimiter() == Delimiter::None => { + tokens.splice(i + 3..i + 4, group.stream()); + } + _ => (), + } + + match &tokens[i] { + TokenTree::Group(group) if group.delimiter() == Delimiter::None => { + tokens.splice(i..i + 1, group.stream()); + } + _ => (), + } + } + } +} |