1 // SPDX-License-Identifier: GPL-2.0 2 3 use proc_macro::{Ident, TokenStream, TokenTree}; 4 use std::collections::BTreeSet; 5 6 /// Please see [`crate::fmt`] for documentation. 7 pub(crate) fn fmt(input: TokenStream) -> TokenStream { 8 let mut input = input.into_iter(); 9 10 let first_opt = input.next(); 11 let first_owned_str; 12 let mut names = BTreeSet::new(); 13 let first_span = { 14 let Some((mut first_str, first_span)) = (match first_opt.as_ref() { 15 Some(TokenTree::Literal(first_lit)) => { 16 first_owned_str = first_lit.to_string(); 17 Some(first_owned_str.as_str()).and_then(|first| { 18 let first = first.strip_prefix('"')?; 19 let first = first.strip_suffix('"')?; 20 Some((first, first_lit.span())) 21 }) 22 } 23 _ => None, 24 }) else { 25 return first_opt.into_iter().chain(input).collect(); 26 }; 27 28 // Parse `identifier`s from the format string. 29 // 30 // See https://doc.rust-lang.org/std/fmt/index.html#syntax. 31 while let Some((_, rest)) = first_str.split_once('{') { 32 first_str = rest; 33 if let Some(rest) = first_str.strip_prefix('{') { 34 first_str = rest; 35 continue; 36 } 37 if let Some((name, rest)) = first_str.split_once('}') { 38 first_str = rest; 39 let name = name.split_once(':').map_or(name, |(name, _)| name); 40 if !name.is_empty() && !name.chars().all(|c| c.is_ascii_digit()) { 41 names.insert(name); 42 } 43 } 44 } 45 first_span 46 }; 47 48 let adapter = quote_spanned!(first_span => ::kernel::fmt::Adapter); 49 50 let mut args = TokenStream::from_iter(first_opt); 51 { 52 let mut flush = |args: &mut TokenStream, current: &mut TokenStream| { 53 let current = std::mem::take(current); 54 if !current.is_empty() { 55 let (lhs, rhs) = (|| { 56 let mut current = current.into_iter(); 57 let mut acc = TokenStream::new(); 58 while let Some(tt) = current.next() { 59 // Split on `=` only once to handle cases like `a = b = c`. 60 if matches!(&tt, TokenTree::Punct(p) if p.as_char() == '=') { 61 names.remove(acc.to_string().as_str()); 62 // Include the `=` itself to keep the handling below uniform. 63 acc.extend([tt]); 64 return (Some(acc), current.collect::<TokenStream>()); 65 } 66 acc.extend([tt]); 67 } 68 (None, acc) 69 })(); 70 args.extend(quote_spanned!(first_span => #lhs #adapter(&#rhs))); 71 } 72 }; 73 74 let mut current = TokenStream::new(); 75 for tt in input { 76 match &tt { 77 TokenTree::Punct(p) if p.as_char() == ',' => { 78 flush(&mut args, &mut current); 79 &mut args 80 } 81 _ => &mut current, 82 } 83 .extend([tt]); 84 } 85 flush(&mut args, &mut current); 86 } 87 88 for name in names { 89 let name = Ident::new(name, first_span); 90 args.extend(quote_spanned!(first_span => , #name = #adapter(&#name))); 91 } 92 93 quote_spanned!(first_span => ::core::format_args!(#args)) 94 } 95