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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/proc-macro-error-attr/src/parse.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/proc-macro-error-attr/src/parse.rs')
-rw-r--r-- | third_party/rust/proc-macro-error-attr/src/parse.rs | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/third_party/rust/proc-macro-error-attr/src/parse.rs b/third_party/rust/proc-macro-error-attr/src/parse.rs new file mode 100644 index 0000000000..6f4663f80e --- /dev/null +++ b/third_party/rust/proc-macro-error-attr/src/parse.rs @@ -0,0 +1,89 @@ +use crate::{Error, Result}; +use proc_macro2::{Delimiter, Ident, Span, TokenStream, TokenTree}; +use quote::ToTokens; +use std::iter::Peekable; + +pub(crate) fn parse_input( + input: TokenStream, +) -> Result<(Vec<Attribute>, Vec<TokenTree>, TokenTree)> { + let mut input = input.into_iter().peekable(); + let mut attrs = Vec::new(); + + while let Some(attr) = parse_next_attr(&mut input)? { + attrs.push(attr); + } + + let sig = parse_signature(&mut input); + let body = input.next().ok_or_else(|| { + Error::new( + Span::call_site(), + "`#[proc_macro_error]` can be applied only to functions".to_string(), + ) + })?; + + Ok((attrs, sig, body)) +} + +fn parse_next_attr( + input: &mut Peekable<impl Iterator<Item = TokenTree>>, +) -> Result<Option<Attribute>> { + let shebang = match input.peek() { + Some(TokenTree::Punct(ref punct)) if punct.as_char() == '#' => input.next().unwrap(), + _ => return Ok(None), + }; + + let group = match input.peek() { + Some(TokenTree::Group(ref group)) if group.delimiter() == Delimiter::Bracket => { + let res = group.clone(); + input.next(); + res + } + other => { + let span = other.map_or(Span::call_site(), |tt| tt.span()); + return Err(Error::new(span, "expected `[`".to_string())); + } + }; + + let path = match group.stream().into_iter().next() { + Some(TokenTree::Ident(ident)) => Some(ident), + _ => None, + }; + + Ok(Some(Attribute { + shebang, + group: TokenTree::Group(group), + path, + })) +} + +fn parse_signature(input: &mut Peekable<impl Iterator<Item = TokenTree>>) -> Vec<TokenTree> { + let mut sig = Vec::new(); + loop { + match input.peek() { + Some(TokenTree::Group(ref group)) if group.delimiter() == Delimiter::Brace => { + return sig; + } + None => return sig, + _ => sig.push(input.next().unwrap()), + } + } +} + +pub(crate) struct Attribute { + pub(crate) shebang: TokenTree, + pub(crate) group: TokenTree, + pub(crate) path: Option<Ident>, +} + +impl Attribute { + pub(crate) fn path_is_ident(&self, ident: &str) -> bool { + self.path.as_ref().map_or(false, |p| *p == ident) + } +} + +impl ToTokens for Attribute { + fn to_tokens(&self, ts: &mut TokenStream) { + self.shebang.to_tokens(ts); + self.group.to_tokens(ts); + } +} |