1 //! Basic syntax highlighting functionality.
3 //! This module uses librustc_ast's lexer to provide token-based highlighting for
4 //! the HTML documentation generated by rustdoc.
6 //! Use the `render_with_highlighting` to highlight some rust code.
8 use crate::clean::PrimitiveType;
9 use crate::html::escape::Escape;
10 use crate::html::render::Context;
12 use std::collections::VecDeque;
13 use std::fmt::{Display, Write};
15 use rustc_data_structures::fx::FxHashMap;
16 use rustc_lexer::{LiteralKind, TokenKind};
17 use rustc_span::edition::Edition;
18 use rustc_span::symbol::Symbol;
19 use rustc_span::{BytePos, Span, DUMMY_SP};
21 use super::format::{self, Buffer};
22 use super::render::LinkFromSrc;
24 /// This type is needed in case we want to render links on items to allow to go to their definition.
25 pub(crate) struct HrefContext<'a, 'b, 'c> {
26 pub(crate) context: &'a Context<'b>,
27 /// This span contains the current file we're going through.
28 pub(crate) file_span: Span,
29 /// This field is used to know "how far" from the top of the directory we are to link to either
30 /// documentation pages or other source pages.
31 pub(crate) root_path: &'c str,
34 /// Decorations are represented as a map from CSS class to vector of character ranges.
35 /// Each range will be wrapped in a span with that class.
37 pub(crate) struct DecorationInfo(pub(crate) FxHashMap<&'static str, Vec<(u32, u32)>>);
39 #[derive(Eq, PartialEq, Clone, Copy)]
40 pub(crate) enum Tooltip {
48 /// Highlights `src` as an inline example, returning the HTML output.
49 pub(crate) fn render_example_with_highlighting(
53 playground_button: Option<&str>,
55 write_header(out, "rust-example-rendered", None, tooltip);
56 write_code(out, src, None, None);
57 write_footer(out, playground_button);
60 /// Highlights `src` as a macro, returning the HTML output.
61 pub(crate) fn render_macro_with_highlighting(src: &str, out: &mut Buffer) {
62 write_header(out, "macro", None, Tooltip::None);
63 write_code(out, src, None, None);
64 write_footer(out, None);
67 /// Highlights `src` as a source code page, returning the HTML output.
68 pub(crate) fn render_source_with_highlighting(
72 href_context: HrefContext<'_, '_, '_>,
73 decoration_info: DecorationInfo,
75 write_header(out, "", Some(line_numbers), Tooltip::None);
76 write_code(out, src, Some(href_context), Some(decoration_info));
77 write_footer(out, None);
80 fn write_header(out: &mut Buffer, class: &str, extra_content: Option<Buffer>, tooltip: Tooltip) {
81 write!(out, "<div class=\"example-wrap\">");
83 let tooltip_class = match tooltip {
84 Tooltip::Ignore => " ignore",
85 Tooltip::CompileFail => " compile_fail",
86 Tooltip::ShouldPanic => " should_panic",
87 Tooltip::Edition(_) => " edition",
91 if tooltip != Tooltip::None {
94 "<div class='information'><div class='tooltip{}'{}>ⓘ</div></div>",
96 if let Tooltip::Edition(edition_info) = tooltip {
97 format!(" data-edition=\"{}\"", edition_info)
104 if let Some(extra) = extra_content {
105 out.push_buffer(extra);
107 if class.is_empty() && tooltip_class.is_empty() {
108 write!(out, "<pre class=\"rust\">");
110 write!(out, "<pre class=\"rust {class}{tooltip_class}\">");
112 write!(out, "<code>");
115 /// Check if two `Class` can be merged together. In the following rules, "unclassified" means `None`
116 /// basically (since it's `Option<Class>`). The following rules apply:
118 /// * If two `Class` have the same variant, then they can be merged.
119 /// * If the other `Class` is unclassified and only contains white characters (backline,
120 /// whitespace, etc), it can be merged.
121 /// * `Class::Ident` is considered the same as unclassified (because it doesn't have an associated
123 fn can_merge(class1: Option<Class>, class2: Option<Class>, text: &str) -> bool {
124 match (class1, class2) {
125 (Some(c1), Some(c2)) => c1.is_equal_to(c2),
126 (Some(Class::Ident(_)), None) | (None, Some(Class::Ident(_))) => true,
127 (Some(_), None) | (None, Some(_)) => text.trim().is_empty(),
128 (None, None) => true,
132 /// This type is used as a conveniency to prevent having to pass all its fields as arguments into
133 /// the various functions (which became its methods).
134 struct TokenHandler<'a, 'b, 'c, 'd, 'e> {
136 /// It contains the closing tag and the associated `Class`.
137 closing_tags: Vec<(&'static str, Class)>,
138 /// This is used because we don't automatically generate the closing tag on `ExitSpan` in
139 /// case an `EnterSpan` event with the same class follows.
140 pending_exit_span: Option<Class>,
141 /// `current_class` and `pending_elems` are used to group HTML elements with same `class`
142 /// attributes to reduce the DOM size.
143 current_class: Option<Class>,
144 /// We need to keep the `Class` for each element because it could contain a `Span` which is
145 /// used to generate links.
146 pending_elems: Vec<(&'b str, Option<Class>)>,
147 href_context: Option<HrefContext<'c, 'd, 'e>>,
150 impl<'a, 'b, 'c, 'd, 'e> TokenHandler<'a, 'b, 'c, 'd, 'e> {
151 fn handle_exit_span(&mut self) {
152 // We can't get the last `closing_tags` element using `pop()` because `closing_tags` is
153 // being used in `write_pending_elems`.
154 let class = self.closing_tags.last().expect("ExitSpan without EnterSpan").1;
155 // We flush everything just in case...
156 self.write_pending_elems(Some(class));
158 exit_span(self.out, self.closing_tags.pop().expect("ExitSpan without EnterSpan").0);
159 self.pending_exit_span = None;
162 /// Write all the pending elements sharing a same (or at mergeable) `Class`.
164 /// If there is a "parent" (if a `EnterSpan` event was encountered) and the parent can be merged
165 /// with the elements' class, then we simply write the elements since the `ExitSpan` event will
168 /// Otherwise, if there is only one pending element, we let the `string` function handle both
169 /// opening and closing the tag, otherwise we do it into this function.
171 /// It returns `true` if `current_class` must be set to `None` afterwards.
172 fn write_pending_elems(&mut self, current_class: Option<Class>) -> bool {
173 if self.pending_elems.is_empty() {
176 if let Some((_, parent_class)) = self.closing_tags.last() &&
177 can_merge(current_class, Some(*parent_class), "")
179 for (text, class) in self.pending_elems.iter() {
180 string(self.out, Escape(text), *class, &self.href_context, false);
183 // We only want to "open" the tag ourselves if we have more than one pending and if the
184 // current parent tag is not the same as our pending content.
185 let close_tag = if self.pending_elems.len() > 1 && current_class.is_some() {
186 Some(enter_span(self.out, current_class.unwrap(), &self.href_context))
190 for (text, class) in self.pending_elems.iter() {
191 string(self.out, Escape(text), *class, &self.href_context, close_tag.is_none());
193 if let Some(close_tag) = close_tag {
194 exit_span(self.out, close_tag);
197 self.pending_elems.clear();
202 impl<'a, 'b, 'c, 'd, 'e> Drop for TokenHandler<'a, 'b, 'c, 'd, 'e> {
203 /// When leaving, we need to flush all pending data to not have missing content.
205 if self.pending_exit_span.is_some() {
206 self.handle_exit_span();
208 self.write_pending_elems(self.current_class);
213 /// Convert the given `src` source code into HTML by adding classes for highlighting.
215 /// This code is used to render code blocks (in the documentation) as well as the source code pages.
217 /// Some explanations on the last arguments:
219 /// In case we are rendering a code block and not a source code file, `href_context` will be `None`.
220 /// To put it more simply: if `href_context` is `None`, the code won't try to generate links to an
223 /// More explanations about spans and how we use them here are provided in the
227 href_context: Option<HrefContext<'_, '_, '_>>,
228 decoration_info: Option<DecorationInfo>,
230 // This replace allows to fix how the code source with DOS backline characters is displayed.
231 let src = src.replace("\r\n", "\n");
232 let mut token_handler = TokenHandler {
234 closing_tags: Vec::new(),
235 pending_exit_span: None,
237 pending_elems: Vec::new(),
243 token_handler.href_context.as_ref().map(|c| c.file_span).unwrap_or(DUMMY_SP),
246 .highlight(&mut |highlight| {
248 Highlight::Token { text, class } => {
249 // If we received a `ExitSpan` event and then have a non-compatible `Class`, we
250 // need to close the `<span>`.
251 let need_current_class_update = if let Some(pending) = token_handler.pending_exit_span &&
252 !can_merge(Some(pending), class, text) {
253 token_handler.handle_exit_span();
255 // If the two `Class` are different, time to flush the current content and start
257 } else if !can_merge(token_handler.current_class, class, text) {
258 token_handler.write_pending_elems(token_handler.current_class);
261 token_handler.current_class.is_none()
264 if need_current_class_update {
265 token_handler.current_class = class.map(Class::dummy);
267 token_handler.pending_elems.push((text, class));
269 Highlight::EnterSpan { class } => {
270 let mut should_add = true;
271 if let Some(pending_exit_span) = token_handler.pending_exit_span {
272 if class.is_equal_to(pending_exit_span) {
275 token_handler.handle_exit_span();
278 // We flush everything just in case...
279 if token_handler.write_pending_elems(token_handler.current_class) {
280 token_handler.current_class = None;
284 let closing_tag = enter_span(token_handler.out, class, &token_handler.href_context);
285 token_handler.closing_tags.push((closing_tag, class));
288 token_handler.current_class = None;
289 token_handler.pending_exit_span = None;
291 Highlight::ExitSpan => {
292 token_handler.current_class = None;
293 token_handler.pending_exit_span =
294 Some(token_handler.closing_tags.last().as_ref().expect("ExitSpan without EnterSpan").1);
300 fn write_footer(out: &mut Buffer, playground_button: Option<&str>) {
301 writeln!(out, "</code></pre>{}</div>", playground_button.unwrap_or_default());
304 /// How a span of text is classified. Mostly corresponds to token kinds.
305 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
311 /// Keywords that do pointer/reference stuff.
319 /// `Ident` isn't rendered in the HTML but we still need it for the `Span` it contains.
325 Decoration(&'static str),
329 /// It is only looking at the variant, not the variant content.
331 /// It is used mostly to group multiple similar HTML elements into one `<span>` instead of
333 fn is_equal_to(self, other: Self) -> bool {
334 match (self, other) {
335 (Self::Self_(_), Self::Self_(_))
336 | (Self::Macro(_), Self::Macro(_))
337 | (Self::Ident(_), Self::Ident(_)) => true,
338 (Self::Decoration(c1), Self::Decoration(c2)) => c1 == c2,
343 /// If `self` contains a `Span`, it'll be replaced with `DUMMY_SP` to prevent creating links
344 /// on "empty content" (because of the attributes merge).
345 fn dummy(self) -> Self {
347 Self::Self_(_) => Self::Self_(DUMMY_SP),
348 Self::Macro(_) => Self::Macro(DUMMY_SP),
349 Self::Ident(_) => Self::Ident(DUMMY_SP),
354 /// Returns the css class expected by rustdoc for each `Class`.
355 fn as_html(self) -> &'static str {
357 Class::Comment => "comment",
358 Class::DocComment => "doccomment",
359 Class::Attribute => "attribute",
360 Class::KeyWord => "kw",
361 Class::RefKeyWord => "kw-2",
362 Class::Self_(_) => "self",
363 Class::Macro(_) => "macro",
364 Class::MacroNonTerminal => "macro-nonterminal",
365 Class::String => "string",
366 Class::Number => "number",
367 Class::Bool => "bool-val",
368 Class::Ident(_) => "",
369 Class::Lifetime => "lifetime",
370 Class::PreludeTy => "prelude-ty",
371 Class::PreludeVal => "prelude-val",
372 Class::QuestionMark => "question-mark",
373 Class::Decoration(kind) => kind,
377 /// In case this is an item which can be converted into a link to a definition, it'll contain
378 /// a "span" (a tuple representing `(lo, hi)` equivalent of `Span`).
379 fn get_span(self) -> Option<Span> {
381 Self::Ident(sp) | Self::Self_(sp) | Self::Macro(sp) => Some(sp),
387 | Self::MacroNonTerminal
395 | Self::Decoration(_) => None,
401 Token { text: &'a str, class: Option<Class> },
402 EnterSpan { class: Class },
406 struct TokenIter<'a> {
410 impl<'a> Iterator for TokenIter<'a> {
411 type Item = (TokenKind, &'a str);
412 fn next(&mut self) -> Option<(TokenKind, &'a str)> {
413 if self.src.is_empty() {
416 let token = rustc_lexer::first_token(self.src);
417 let (text, rest) = self.src.split_at(token.len as usize);
419 Some((token.kind, text))
423 /// Classifies into identifier class; returns `None` if this is a non-keyword identifier.
424 fn get_real_ident_class(text: &str, allow_path_keywords: bool) -> Option<Class> {
425 let ignore: &[&str] =
426 if allow_path_keywords { &["self", "Self", "super", "crate"] } else { &["self", "Self"] };
427 if ignore.iter().any(|k| *k == text) {
431 "ref" | "mut" => Class::RefKeyWord,
432 "false" | "true" => Class::Bool,
433 _ if Symbol::intern(text).is_reserved(|| Edition::Edition2021) => Class::KeyWord,
438 /// This iterator comes from the same idea than "Peekable" except that it allows to "peek" more than
439 /// just the next item by using `peek_next`. The `peek` method always returns the next item after
440 /// the current one whereas `peek_next` will return the next item after the last one peeked.
442 /// You can use both `peek` and `peek_next` at the same time without problem.
443 struct PeekIter<'a> {
444 stored: VecDeque<(TokenKind, &'a str)>,
445 /// This position is reinitialized when using `next`. It is used in `peek_next`.
450 impl<'a> PeekIter<'a> {
451 fn new(iter: TokenIter<'a>) -> Self {
452 Self { stored: VecDeque::new(), peek_pos: 0, iter }
454 /// Returns the next item after the current one. It doesn't interfere with `peek_next` output.
455 fn peek(&mut self) -> Option<&(TokenKind, &'a str)> {
456 if self.stored.is_empty() {
457 if let Some(next) = self.iter.next() {
458 self.stored.push_back(next);
463 /// Returns the next item after the last one peeked. It doesn't interfere with `peek` output.
464 fn peek_next(&mut self) -> Option<&(TokenKind, &'a str)> {
466 if self.peek_pos - 1 < self.stored.len() {
467 self.stored.get(self.peek_pos - 1)
468 } else if let Some(next) = self.iter.next() {
469 self.stored.push_back(next);
477 impl<'a> Iterator for PeekIter<'a> {
478 type Item = (TokenKind, &'a str);
479 fn next(&mut self) -> Option<Self::Item> {
481 if let Some(first) = self.stored.pop_front() { Some(first) } else { self.iter.next() }
485 /// Custom spans inserted into the source. Eg --scrape-examples uses this to highlight function calls
487 starts: Vec<(u32, &'static str)>,
492 fn new(info: DecorationInfo) -> Self {
493 // Extract tuples (start, end, kind) into separate sequences of (start, kind) and (end).
494 let (mut starts, mut ends): (Vec<_>, Vec<_>) = info
497 .flat_map(|(kind, ranges)| ranges.into_iter().map(move |(lo, hi)| ((lo, kind), hi)))
500 // Sort the sequences in document order.
501 starts.sort_by_key(|(lo, _)| *lo);
504 Decorations { starts, ends }
508 /// Processes program tokens, classifying strings of text by highlighting
509 /// category (`Class`).
510 struct Classifier<'a> {
511 tokens: PeekIter<'a>,
514 in_macro_nonterminal: bool,
518 decorations: Option<Decorations>,
521 impl<'a> Classifier<'a> {
522 /// Takes as argument the source code to HTML-ify, the rust edition to use and the source code
523 /// file span which will be used later on by the `span_correspondance_map`.
524 fn new(src: &str, file_span: Span, decoration_info: Option<DecorationInfo>) -> Classifier<'_> {
525 let tokens = PeekIter::new(TokenIter { src });
526 let decorations = decoration_info.map(Decorations::new);
531 in_macro_nonterminal: false,
539 /// Convenient wrapper to create a [`Span`] from a position in the file.
540 fn new_span(&self, lo: u32, text: &str) -> Span {
541 let hi = lo + text.len() as u32;
542 let file_lo = self.file_span.lo();
543 self.file_span.with_lo(file_lo + BytePos(lo)).with_hi(file_lo + BytePos(hi))
546 /// Concatenate colons and idents as one when possible.
547 fn get_full_ident_path(&mut self) -> Vec<(TokenKind, usize, usize)> {
548 let start = self.byte_pos as usize;
550 let mut has_ident = false;
554 while let Some((TokenKind::Colon, _)) = self.tokens.peek() {
558 // Ident path can start with "::" but if we already have content in the ident path,
559 // the "::" is mandatory.
560 if has_ident && nb == 0 {
561 return vec![(TokenKind::Ident, start, pos)];
562 } else if nb != 0 && nb != 2 {
564 return vec![(TokenKind::Ident, start, pos), (TokenKind::Colon, pos, pos + nb)];
566 return vec![(TokenKind::Colon, start, pos + nb)];
570 if let Some((None, text)) = self.tokens.peek().map(|(token, text)| {
571 if *token == TokenKind::Ident {
572 let class = get_real_ident_class(text, true);
575 // Doesn't matter which Class we put in here...
576 (Some(Class::Comment), text)
579 // We only "add" the colon if there is an ident behind.
580 pos += text.len() + nb;
583 } else if nb > 0 && has_ident {
584 return vec![(TokenKind::Ident, start, pos), (TokenKind::Colon, pos, pos + nb)];
586 return vec![(TokenKind::Colon, start, start + nb)];
587 } else if has_ident {
588 return vec![(TokenKind::Ident, start, pos)];
595 /// Wraps the tokens iteration to ensure that the `byte_pos` is always correct.
597 /// It returns the token's kind, the token as a string and its byte position in the source
599 fn next(&mut self) -> Option<(TokenKind, &'a str, u32)> {
600 if let Some((kind, text)) = self.tokens.next() {
601 let before = self.byte_pos;
602 self.byte_pos += text.len() as u32;
603 Some((kind, text, before))
609 /// Exhausts the `Classifier` writing the output into `sink`.
611 /// The general structure for this method is to iterate over each token,
612 /// possibly giving it an HTML span with a class specifying what flavor of
614 fn highlight(mut self, sink: &mut dyn FnMut(Highlight<'a>)) {
616 if let Some(decs) = self.decorations.as_mut() {
617 let byte_pos = self.byte_pos;
618 let n_starts = decs.starts.iter().filter(|(i, _)| byte_pos >= *i).count();
619 for (_, kind) in decs.starts.drain(0..n_starts) {
620 sink(Highlight::EnterSpan { class: Class::Decoration(kind) });
623 let n_ends = decs.ends.iter().filter(|i| byte_pos >= **i).count();
624 for _ in decs.ends.drain(0..n_ends) {
625 sink(Highlight::ExitSpan);
632 .map(|t| matches!(t.0, TokenKind::Colon | TokenKind::Ident))
635 let tokens = self.get_full_ident_path();
636 for (token, start, end) in &tokens {
637 let text = &self.src[*start..*end];
638 self.advance(*token, text, sink, *start as u32);
639 self.byte_pos += text.len() as u32;
641 if !tokens.is_empty() {
645 if let Some((token, text, before)) = self.next() {
646 self.advance(token, text, sink, before);
653 /// Single step of highlighting. This will classify `token`, but maybe also a couple of
654 /// following ones as well.
656 /// `before` is the position of the given token in the `source` string and is used as "lo" byte
657 /// in case we want to try to generate a link for this token using the
658 /// `span_correspondance_map`.
663 sink: &mut dyn FnMut(Highlight<'a>),
666 let lookahead = self.peek();
667 let no_highlight = |sink: &mut dyn FnMut(_)| sink(Highlight::Token { text, class: None });
668 let class = match token {
669 TokenKind::Whitespace => return no_highlight(sink),
670 TokenKind::LineComment { doc_style } | TokenKind::BlockComment { doc_style, .. } => {
671 if doc_style.is_some() {
677 // Consider this as part of a macro invocation if there was a
678 // leading identifier.
679 TokenKind::Bang if self.in_macro => {
680 self.in_macro = false;
681 sink(Highlight::Token { text, class: None });
682 sink(Highlight::ExitSpan);
686 // Assume that '&' or '*' is the reference or dereference operator
687 // or a reference or pointer type. Unless, of course, it looks like
688 // a logical and or a multiplication operator: `&&` or `* `.
689 TokenKind::Star => match self.tokens.peek() {
690 Some((TokenKind::Whitespace, _)) => return no_highlight(sink),
691 Some((TokenKind::Ident, "mut")) => {
693 sink(Highlight::Token { text: "*mut", class: Some(Class::RefKeyWord) });
696 Some((TokenKind::Ident, "const")) => {
698 sink(Highlight::Token { text: "*const", class: Some(Class::RefKeyWord) });
701 _ => Class::RefKeyWord,
703 TokenKind::And => match self.tokens.peek() {
704 Some((TokenKind::And, _)) => {
706 sink(Highlight::Token { text: "&&", class: None });
709 Some((TokenKind::Eq, _)) => {
711 sink(Highlight::Token { text: "&=", class: None });
714 Some((TokenKind::Whitespace, _)) => return no_highlight(sink),
715 Some((TokenKind::Ident, "mut")) => {
717 sink(Highlight::Token { text: "&mut", class: Some(Class::RefKeyWord) });
720 _ => Class::RefKeyWord,
723 // These can either be operators, or arrows.
724 TokenKind::Eq => match lookahead {
725 Some(TokenKind::Eq) => {
727 sink(Highlight::Token { text: "==", class: None });
730 Some(TokenKind::Gt) => {
732 sink(Highlight::Token { text: "=>", class: None });
735 _ => return no_highlight(sink),
737 TokenKind::Minus if lookahead == Some(TokenKind::Gt) => {
739 sink(Highlight::Token { text: "->", class: None });
752 | TokenKind::Gt => return no_highlight(sink),
754 // Miscellaneous, no highlighting.
758 | TokenKind::OpenParen
759 | TokenKind::CloseParen
760 | TokenKind::OpenBrace
761 | TokenKind::CloseBrace
762 | TokenKind::OpenBracket
766 | TokenKind::Unknown => return no_highlight(sink),
768 TokenKind::Question => Class::QuestionMark,
770 TokenKind::Dollar => match lookahead {
771 Some(TokenKind::Ident) => {
772 self.in_macro_nonterminal = true;
773 Class::MacroNonTerminal
775 _ => return no_highlight(sink),
778 // This might be the start of an attribute. We're going to want to
779 // continue highlighting it as an attribute until the ending ']' is
780 // seen, so skip out early. Down below we terminate the attribute
781 // span when we see the ']'.
782 TokenKind::Pound => {
784 // Case 1: #![inner_attribute]
785 Some(TokenKind::Bang) => {
787 if let Some(TokenKind::OpenBracket) = self.peek() {
788 self.in_attribute = true;
789 sink(Highlight::EnterSpan { class: Class::Attribute });
791 sink(Highlight::Token { text: "#", class: None });
792 sink(Highlight::Token { text: "!", class: None });
795 // Case 2: #[outer_attribute]
796 Some(TokenKind::OpenBracket) => {
797 self.in_attribute = true;
798 sink(Highlight::EnterSpan { class: Class::Attribute });
802 return no_highlight(sink);
804 TokenKind::CloseBracket => {
805 if self.in_attribute {
806 self.in_attribute = false;
807 sink(Highlight::Token { text: "]", class: None });
808 sink(Highlight::ExitSpan);
811 return no_highlight(sink);
813 TokenKind::Literal { kind, .. } => match kind {
815 LiteralKind::Byte { .. }
816 | LiteralKind::Char { .. }
817 | LiteralKind::Str { .. }
818 | LiteralKind::ByteStr { .. }
819 | LiteralKind::RawStr { .. }
820 | LiteralKind::RawByteStr { .. } => Class::String,
822 LiteralKind::Float { .. } | LiteralKind::Int { .. } => Class::Number,
824 TokenKind::Ident | TokenKind::RawIdent if lookahead == Some(TokenKind::Bang) => {
825 self.in_macro = true;
826 sink(Highlight::EnterSpan { class: Class::Macro(self.new_span(before, text)) });
827 sink(Highlight::Token { text, class: None });
830 TokenKind::Ident => match get_real_ident_class(text, false) {
832 "Option" | "Result" => Class::PreludeTy,
833 "Some" | "None" | "Ok" | "Err" => Class::PreludeVal,
834 // "union" is a weak keyword and is only considered as a keyword when declaring
836 "union" if self.check_if_is_union_keyword() => Class::KeyWord,
837 _ if self.in_macro_nonterminal => {
838 self.in_macro_nonterminal = false;
839 Class::MacroNonTerminal
841 "self" | "Self" => Class::Self_(self.new_span(before, text)),
842 _ => Class::Ident(self.new_span(before, text)),
846 TokenKind::RawIdent | TokenKind::UnknownPrefix | TokenKind::InvalidIdent => {
847 Class::Ident(self.new_span(before, text))
849 TokenKind::Lifetime { .. } => Class::Lifetime,
851 // Anything that didn't return above is the simple case where we the
852 // class just spans a single token, so we can use the `string` method.
853 sink(Highlight::Token { text, class: Some(class) });
856 fn peek(&mut self) -> Option<TokenKind> {
857 self.tokens.peek().map(|(token_kind, _text)| *token_kind)
860 fn check_if_is_union_keyword(&mut self) -> bool {
861 while let Some(kind) = self.tokens.peek_next().map(|(token_kind, _text)| token_kind) {
862 if *kind == TokenKind::Whitespace {
865 return *kind == TokenKind::Ident;
871 /// Called when we start processing a span of text that should be highlighted.
872 /// The `Class` argument specifies how it should be highlighted.
876 href_context: &Option<HrefContext<'_, '_, '_>>,
878 string_without_closing_tag(out, "", Some(klass), href_context, true).expect(
879 "internal error: enter_span was called with Some(klass) but did not return a \
884 /// Called at the end of a span of highlighted text.
885 fn exit_span(out: &mut Buffer, closing_tag: &str) {
886 out.write_str(closing_tag);
889 /// Called for a span of text. If the text should be highlighted differently
890 /// from the surrounding text, then the `Class` argument will be a value other
893 /// The following sequences of callbacks are equivalent:
895 /// enter_span(Foo), string("text", None), exit_span()
896 /// string("text", Foo)
899 /// The latter can be thought of as a shorthand for the former, which is more
902 /// Note that if `context` is not `None` and that the given `klass` contains a `Span`, the function
903 /// will then try to find this `span` in the `span_correspondance_map`. If found, it'll then
904 /// generate a link for this element (which corresponds to where its definition is located).
905 fn string<T: Display>(
908 klass: Option<Class>,
909 href_context: &Option<HrefContext<'_, '_, '_>>,
912 if let Some(closing_tag) = string_without_closing_tag(out, text, klass, href_context, open_tag)
914 out.write_str(closing_tag);
918 /// This function writes `text` into `out` with some modifications depending on `klass`:
920 /// * If `klass` is `None`, `text` is written into `out` with no modification.
921 /// * If `klass` is `Some` but `klass.get_span()` is `None`, it writes the text wrapped in a
922 /// `<span>` with the provided `klass`.
923 /// * If `klass` is `Some` and has a [`rustc_span::Span`], it then tries to generate a link (`<a>`
924 /// element) by retrieving the link information from the `span_correspondance_map` that was filled
925 /// in `span_map.rs::collect_spans_and_sources`. If it cannot retrieve the information, then it's
926 /// the same as the second point (`klass` is `Some` but doesn't have a [`rustc_span::Span`]).
927 fn string_without_closing_tag<T: Display>(
930 klass: Option<Class>,
931 href_context: &Option<HrefContext<'_, '_, '_>>,
933 ) -> Option<&'static str> {
934 let Some(klass) = klass
936 write!(out, "{}", text);
939 let Some(def_span) = klass.get_span()
942 write!(out, "{}", text);
945 write!(out, "<span class=\"{}\">{}", klass.as_html(), text);
946 return Some("</span>");
949 let mut text_s = text.to_string();
950 if text_s.contains("::") {
951 text_s = text_s.split("::").intersperse("::").fold(String::new(), |mut path, t| {
953 "self" | "Self" => write!(
955 "<span class=\"{}\">{}</span>",
956 Class::Self_(DUMMY_SP).as_html(),
959 "crate" | "super" => {
960 write!(&mut path, "<span class=\"{}\">{}</span>", Class::KeyWord.as_html(), t)
962 t => write!(&mut path, "{}", t),
964 .expect("Failed to build source HTML path");
969 if let Some(href_context) = href_context {
971 href_context.context.shared.span_correspondance_map.get(&def_span).and_then(|href| {
972 let context = href_context.context;
973 // FIXME: later on, it'd be nice to provide two links (if possible) for all items:
974 // one to the documentation page and one to the source definition.
975 // FIXME: currently, external items only generate a link to their documentation,
976 // a link to their definition can be generated using this:
977 // https://github.com/rust-lang/rust/blob/60f1a2fc4b535ead9c85ce085fdce49b1b097531/src/librustdoc/html/render/context.rs#L315-L338
979 LinkFromSrc::Local(span) => context
980 .href_from_span(*span, true)
981 .map(|s| format!("{}{}", href_context.root_path, s)),
982 LinkFromSrc::External(def_id) => {
983 format::href_with_root_path(*def_id, context, Some(href_context.root_path))
985 .map(|(url, _, _)| url)
987 LinkFromSrc::Primitive(prim) => format::href_with_root_path(
988 PrimitiveType::primitive_locations(context.tcx())[prim],
990 Some(href_context.root_path),
993 .map(|(url, _, _)| url),
998 // We're already inside an element which has the same klass, no need to give it
1000 write!(out, "<a href=\"{}\">{}", href, text_s);
1002 let klass_s = klass.as_html();
1003 if klass_s.is_empty() {
1004 write!(out, "<a href=\"{}\">{}", href, text_s);
1006 write!(out, "<a class=\"{}\" href=\"{}\">{}", klass_s, href, text_s);
1009 return Some("</a>");
1013 write!(out, "{}", text_s);
1016 let klass_s = klass.as_html();
1017 if klass_s.is_empty() {
1018 write!(out, "{}", text_s);
1021 write!(out, "<span class=\"{}\">{}", klass_s, text_s);