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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/paste/src/lib.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/paste/src/lib.rs')
-rw-r--r-- | third_party/rust/paste/src/lib.rs | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/third_party/rust/paste/src/lib.rs b/third_party/rust/paste/src/lib.rs new file mode 100644 index 0000000000..80c1b98f46 --- /dev/null +++ b/third_party/rust/paste/src/lib.rs @@ -0,0 +1,453 @@ +//! [![github]](https://github.com/dtolnay/paste) [![crates-io]](https://crates.io/crates/paste) [![docs-rs]](https://docs.rs/paste) +//! +//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github +//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust +//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs +//! +//! <br> +//! +//! The nightly-only [`concat_idents!`] macro in the Rust standard library is +//! notoriously underpowered in that its concatenated identifiers can only refer to +//! existing items, they can never be used to define something new. +//! +//! [`concat_idents!`]: https://doc.rust-lang.org/std/macro.concat_idents.html +//! +//! This crate provides a flexible way to paste together identifiers in a macro, +//! including using pasted identifiers to define new items. +//! +//! This approach works with any Rust compiler 1.31+. +//! +//! <br> +//! +//! # Pasting identifiers +//! +//! Within the `paste!` macro, identifiers inside `[<`...`>]` are pasted +//! together to form a single identifier. +//! +//! ``` +//! use paste::paste; +//! +//! paste! { +//! // Defines a const called `QRST`. +//! const [<Q R S T>]: &str = "success!"; +//! } +//! +//! fn main() { +//! assert_eq!( +//! paste! { [<Q R S T>].len() }, +//! 8, +//! ); +//! } +//! ``` +//! +//! <br><br> +//! +//! # More elaborate example +//! +//! The next example shows a macro that generates accessor methods for some +//! struct fields. It demonstrates how you might find it useful to bundle a +//! paste invocation inside of a macro\_rules macro. +//! +//! ``` +//! use paste::paste; +//! +//! macro_rules! make_a_struct_and_getters { +//! ($name:ident { $($field:ident),* }) => { +//! // Define a struct. This expands to: +//! // +//! // pub struct S { +//! // a: String, +//! // b: String, +//! // c: String, +//! // } +//! pub struct $name { +//! $( +//! $field: String, +//! )* +//! } +//! +//! // Build an impl block with getters. This expands to: +//! // +//! // impl S { +//! // pub fn get_a(&self) -> &str { &self.a } +//! // pub fn get_b(&self) -> &str { &self.b } +//! // pub fn get_c(&self) -> &str { &self.c } +//! // } +//! paste! { +//! impl $name { +//! $( +//! pub fn [<get_ $field>](&self) -> &str { +//! &self.$field +//! } +//! )* +//! } +//! } +//! } +//! } +//! +//! make_a_struct_and_getters!(S { a, b, c }); +//! +//! fn call_some_getters(s: &S) -> bool { +//! s.get_a() == s.get_b() && s.get_c().is_empty() +//! } +//! # +//! # fn main() {} +//! ``` +//! +//! <br><br> +//! +//! # Case conversion +//! +//! Use `$var:lower` or `$var:upper` in the segment list to convert an +//! interpolated segment to lower- or uppercase as part of the paste. For +//! example, `[<ld_ $reg:lower _expr>]` would paste to `ld_bc_expr` if invoked +//! with $reg=`Bc`. +//! +//! Use `$var:snake` to convert CamelCase input to snake\_case. +//! Use `$var:camel` to convert snake\_case to CamelCase. +//! These compose, so for example `$var:snake:upper` would give you SCREAMING\_CASE. +//! +//! The precise Unicode conversions are as defined by [`str::to_lowercase`] and +//! [`str::to_uppercase`]. +//! +//! [`str::to_lowercase`]: https://doc.rust-lang.org/std/primitive.str.html#method.to_lowercase +//! [`str::to_uppercase`]: https://doc.rust-lang.org/std/primitive.str.html#method.to_uppercase +//! +//! <br> +//! +//! # Pasting documentation strings +//! +//! Within the `paste!` macro, arguments to a #\[doc ...\] attribute are +//! implicitly concatenated together to form a coherent documentation string. +//! +//! ``` +//! use paste::paste; +//! +//! macro_rules! method_new { +//! ($ret:ident) => { +//! paste! { +//! #[doc = "Create a new `" $ret "` object."] +//! pub fn new() -> $ret { todo!() } +//! } +//! }; +//! } +//! +//! pub struct Paste {} +//! +//! method_new!(Paste); // expands to #[doc = "Create a new `Paste` object"] +//! ``` + +#![allow( + clippy::derive_partial_eq_without_eq, + clippy::doc_markdown, + clippy::match_same_arms, + clippy::module_name_repetitions, + clippy::needless_doctest_main, + clippy::too_many_lines +)] + +extern crate proc_macro; + +mod attr; +mod error; +mod segment; + +use crate::attr::expand_attr; +use crate::error::{Error, Result}; +use crate::segment::Segment; +use proc_macro::{Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree}; +use std::char; +use std::iter; +use std::panic; + +#[proc_macro] +pub fn paste(input: TokenStream) -> TokenStream { + let mut contains_paste = false; + let flatten_single_interpolation = true; + match expand( + input.clone(), + &mut contains_paste, + flatten_single_interpolation, + ) { + Ok(expanded) => { + if contains_paste { + expanded + } else { + input + } + } + Err(err) => err.to_compile_error(), + } +} + +#[doc(hidden)] +#[proc_macro] +pub fn item(input: TokenStream) -> TokenStream { + paste(input) +} + +#[doc(hidden)] +#[proc_macro] +pub fn expr(input: TokenStream) -> TokenStream { + paste(input) +} + +fn expand( + input: TokenStream, + contains_paste: &mut bool, + flatten_single_interpolation: bool, +) -> Result<TokenStream> { + let mut expanded = TokenStream::new(); + let mut lookbehind = Lookbehind::Other; + let mut prev_none_group = None::<Group>; + let mut tokens = input.into_iter().peekable(); + loop { + let token = tokens.next(); + if let Some(group) = prev_none_group.take() { + if match (&token, tokens.peek()) { + (Some(TokenTree::Punct(fst)), Some(TokenTree::Punct(snd))) => { + fst.as_char() == ':' && snd.as_char() == ':' && fst.spacing() == Spacing::Joint + } + _ => false, + } { + expanded.extend(group.stream()); + *contains_paste = true; + } else { + expanded.extend(iter::once(TokenTree::Group(group))); + } + } + match token { + Some(TokenTree::Group(group)) => { + let delimiter = group.delimiter(); + let content = group.stream(); + let span = group.span(); + if delimiter == Delimiter::Bracket && is_paste_operation(&content) { + let segments = parse_bracket_as_segments(content, span)?; + let pasted = segment::paste(&segments)?; + let tokens = pasted_to_tokens(pasted, span)?; + expanded.extend(tokens); + *contains_paste = true; + } else if flatten_single_interpolation + && delimiter == Delimiter::None + && is_single_interpolation_group(&content) + { + expanded.extend(content); + *contains_paste = true; + } else { + let mut group_contains_paste = false; + let is_attribute = delimiter == Delimiter::Bracket + && (lookbehind == Lookbehind::Pound || lookbehind == Lookbehind::PoundBang); + let mut nested = expand( + content, + &mut group_contains_paste, + flatten_single_interpolation && !is_attribute, + )?; + if is_attribute { + nested = expand_attr(nested, span, &mut group_contains_paste)?; + } + let group = if group_contains_paste { + let mut group = Group::new(delimiter, nested); + group.set_span(span); + *contains_paste = true; + group + } else { + group.clone() + }; + if delimiter != Delimiter::None { + expanded.extend(iter::once(TokenTree::Group(group))); + } else if lookbehind == Lookbehind::DoubleColon { + expanded.extend(group.stream()); + *contains_paste = true; + } else { + prev_none_group = Some(group); + } + } + lookbehind = Lookbehind::Other; + } + Some(TokenTree::Punct(punct)) => { + lookbehind = match punct.as_char() { + ':' if lookbehind == Lookbehind::JointColon => Lookbehind::DoubleColon, + ':' if punct.spacing() == Spacing::Joint => Lookbehind::JointColon, + '#' => Lookbehind::Pound, + '!' if lookbehind == Lookbehind::Pound => Lookbehind::PoundBang, + _ => Lookbehind::Other, + }; + expanded.extend(iter::once(TokenTree::Punct(punct))); + } + Some(other) => { + lookbehind = Lookbehind::Other; + expanded.extend(iter::once(other)); + } + None => return Ok(expanded), + } + } +} + +#[derive(PartialEq)] +enum Lookbehind { + JointColon, + DoubleColon, + Pound, + PoundBang, + Other, +} + +// https://github.com/dtolnay/paste/issues/26 +fn is_single_interpolation_group(input: &TokenStream) -> bool { + #[derive(PartialEq)] + enum State { + Init, + Ident, + Literal, + Apostrophe, + Lifetime, + Colon1, + Colon2, + } + + let mut state = State::Init; + for tt in input.clone() { + state = match (state, &tt) { + (State::Init, TokenTree::Ident(_)) => State::Ident, + (State::Init, TokenTree::Literal(_)) => State::Literal, + (State::Init, TokenTree::Punct(punct)) if punct.as_char() == '\'' => State::Apostrophe, + (State::Apostrophe, TokenTree::Ident(_)) => State::Lifetime, + (State::Ident, TokenTree::Punct(punct)) + if punct.as_char() == ':' && punct.spacing() == Spacing::Joint => + { + State::Colon1 + } + (State::Colon1, TokenTree::Punct(punct)) + if punct.as_char() == ':' && punct.spacing() == Spacing::Alone => + { + State::Colon2 + } + (State::Colon2, TokenTree::Ident(_)) => State::Ident, + _ => return false, + }; + } + + state == State::Ident || state == State::Literal || state == State::Lifetime +} + +fn is_paste_operation(input: &TokenStream) -> bool { + let mut tokens = input.clone().into_iter(); + + match &tokens.next() { + Some(TokenTree::Punct(punct)) if punct.as_char() == '<' => {} + _ => return false, + } + + let mut has_token = false; + loop { + match &tokens.next() { + Some(TokenTree::Punct(punct)) if punct.as_char() == '>' => { + return has_token && tokens.next().is_none(); + } + Some(_) => has_token = true, + None => return false, + } + } +} + +fn parse_bracket_as_segments(input: TokenStream, scope: Span) -> Result<Vec<Segment>> { + let mut tokens = input.into_iter().peekable(); + + match &tokens.next() { + Some(TokenTree::Punct(punct)) if punct.as_char() == '<' => {} + Some(wrong) => return Err(Error::new(wrong.span(), "expected `<`")), + None => return Err(Error::new(scope, "expected `[< ... >]`")), + } + + let mut segments = segment::parse(&mut tokens)?; + + match &tokens.next() { + Some(TokenTree::Punct(punct)) if punct.as_char() == '>' => {} + Some(wrong) => return Err(Error::new(wrong.span(), "expected `>`")), + None => return Err(Error::new(scope, "expected `[< ... >]`")), + } + + if let Some(unexpected) = tokens.next() { + return Err(Error::new( + unexpected.span(), + "unexpected input, expected `[< ... >]`", + )); + } + + for segment in &mut segments { + if let Segment::String(string) = segment { + if string.value.starts_with("'\\u{") { + let hex = &string.value[4..string.value.len() - 2]; + if let Ok(unsigned) = u32::from_str_radix(hex, 16) { + if let Some(ch) = char::from_u32(unsigned) { + string.value.clear(); + string.value.push(ch); + continue; + } + } + } + if string.value.contains(&['#', '\\', '.', '+'][..]) + || string.value.starts_with("b'") + || string.value.starts_with("b\"") + || string.value.starts_with("br\"") + { + return Err(Error::new(string.span, "unsupported literal")); + } + let mut range = 0..string.value.len(); + if string.value.starts_with("r\"") { + range.start += 2; + range.end -= 1; + } else if string.value.starts_with(&['"', '\''][..]) { + range.start += 1; + range.end -= 1; + } + string.value = string.value[range].replace('-', "_"); + } + } + + Ok(segments) +} + +fn pasted_to_tokens(mut pasted: String, span: Span) -> Result<TokenStream> { + let mut tokens = TokenStream::new(); + + #[cfg(not(no_literal_fromstr))] + { + use proc_macro::{LexError, Literal}; + use std::str::FromStr; + + if pasted.starts_with(|ch: char| ch.is_ascii_digit()) { + let literal = match panic::catch_unwind(|| Literal::from_str(&pasted)) { + Ok(Ok(literal)) => TokenTree::Literal(literal), + Ok(Err(LexError { .. })) | Err(_) => { + return Err(Error::new( + span, + &format!("`{:?}` is not a valid literal", pasted), + )); + } + }; + tokens.extend(iter::once(literal)); + return Ok(tokens); + } + } + + if pasted.starts_with('\'') { + let mut apostrophe = TokenTree::Punct(Punct::new('\'', Spacing::Joint)); + apostrophe.set_span(span); + tokens.extend(iter::once(apostrophe)); + pasted.remove(0); + } + + let ident = match panic::catch_unwind(|| Ident::new(&pasted, span)) { + Ok(ident) => TokenTree::Ident(ident), + Err(_) => { + return Err(Error::new( + span, + &format!("`{:?}` is not a valid identifier", pasted), + )); + } + }; + + tokens.extend(iter::once(ident)); + Ok(tokens) +} |