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) {
83 "<div class=\"example-wrap{}\">",
85 Tooltip::Ignore => " ignore",
86 Tooltip::CompileFail => " compile_fail",
87 Tooltip::ShouldPanic => " should_panic",
88 Tooltip::Edition(_) => " edition",
93 if tooltip != Tooltip::None {
96 "<div class='tooltip'{}>ⓘ</div>",
97 if let Tooltip::Edition(edition_info) = tooltip {
98 format!(" data-edition=\"{}\"", edition_info)
105 if let Some(extra) = extra_content {
106 out.push_buffer(extra);
108 if class.is_empty() {
109 write!(out, "<pre class=\"rust\">");
111 write!(out, "<pre class=\"rust {class}\">");
113 write!(out, "<code>");
116 /// Check if two `Class` can be merged together. In the following rules, "unclassified" means `None`
117 /// basically (since it's `Option<Class>`). The following rules apply:
119 /// * If two `Class` have the same variant, then they can be merged.
120 /// * If the other `Class` is unclassified and only contains white characters (backline,
121 /// whitespace, etc), it can be merged.
122 /// * `Class::Ident` is considered the same as unclassified (because it doesn't have an associated
124 fn can_merge(class1: Option<Class>, class2: Option<Class>, text: &str) -> bool {
125 match (class1, class2) {
126 (Some(c1), Some(c2)) => c1.is_equal_to(c2),
127 (Some(Class::Ident(_)), None) | (None, Some(Class::Ident(_))) => true,
128 (Some(_), None) | (None, Some(_)) => text.trim().is_empty(),
129 (None, None) => true,
133 /// This type is used as a conveniency to prevent having to pass all its fields as arguments into
134 /// the various functions (which became its methods).
135 struct TokenHandler<'a, 'b, 'c, 'd, 'e> {
137 /// It contains the closing tag and the associated `Class`.
138 closing_tags: Vec<(&'static str, Class)>,
139 /// This is used because we don't automatically generate the closing tag on `ExitSpan` in
140 /// case an `EnterSpan` event with the same class follows.
141 pending_exit_span: Option<Class>,
142 /// `current_class` and `pending_elems` are used to group HTML elements with same `class`
143 /// attributes to reduce the DOM size.
144 current_class: Option<Class>,
145 /// We need to keep the `Class` for each element because it could contain a `Span` which is
146 /// used to generate links.
147 pending_elems: Vec<(&'b str, Option<Class>)>,
148 href_context: Option<HrefContext<'c, 'd, 'e>>,
151 impl<'a, 'b, 'c, 'd, 'e> TokenHandler<'a, 'b, 'c, 'd, 'e> {
152 fn handle_exit_span(&mut self) {
153 // We can't get the last `closing_tags` element using `pop()` because `closing_tags` is
154 // being used in `write_pending_elems`.
155 let class = self.closing_tags.last().expect("ExitSpan without EnterSpan").1;
156 // We flush everything just in case...
157 self.write_pending_elems(Some(class));
159 exit_span(self.out, self.closing_tags.pop().expect("ExitSpan without EnterSpan").0);
160 self.pending_exit_span = None;
163 /// Write all the pending elements sharing a same (or at mergeable) `Class`.
165 /// If there is a "parent" (if a `EnterSpan` event was encountered) and the parent can be merged
166 /// with the elements' class, then we simply write the elements since the `ExitSpan` event will
169 /// Otherwise, if there is only one pending element, we let the `string` function handle both
170 /// opening and closing the tag, otherwise we do it into this function.
172 /// It returns `true` if `current_class` must be set to `None` afterwards.
173 fn write_pending_elems(&mut self, current_class: Option<Class>) -> bool {
174 if self.pending_elems.is_empty() {
177 if let Some((_, parent_class)) = self.closing_tags.last() &&
178 can_merge(current_class, Some(*parent_class), "")
180 for (text, class) in self.pending_elems.iter() {
181 string(self.out, Escape(text), *class, &self.href_context, false);
184 // We only want to "open" the tag ourselves if we have more than one pending and if the
185 // current parent tag is not the same as our pending content.
186 let close_tag = if self.pending_elems.len() > 1 && current_class.is_some() {
187 Some(enter_span(self.out, current_class.unwrap(), &self.href_context))
191 for (text, class) in self.pending_elems.iter() {
192 string(self.out, Escape(text), *class, &self.href_context, close_tag.is_none());
194 if let Some(close_tag) = close_tag {
195 exit_span(self.out, close_tag);
198 self.pending_elems.clear();
203 impl<'a, 'b, 'c, 'd, 'e> Drop for TokenHandler<'a, 'b, 'c, 'd, 'e> {
204 /// When leaving, we need to flush all pending data to not have missing content.
206 if self.pending_exit_span.is_some() {
207 self.handle_exit_span();
209 self.write_pending_elems(self.current_class);
214 /// Convert the given `src` source code into HTML by adding classes for highlighting.
216 /// This code is used to render code blocks (in the documentation) as well as the source code pages.
218 /// Some explanations on the last arguments:
220 /// In case we are rendering a code block and not a source code file, `href_context` will be `None`.
221 /// To put it more simply: if `href_context` is `None`, the code won't try to generate links to an
224 /// More explanations about spans and how we use them here are provided in the
228 href_context: Option<HrefContext<'_, '_, '_>>,
229 decoration_info: Option<DecorationInfo>,
231 // This replace allows to fix how the code source with DOS backline characters is displayed.
232 let src = src.replace("\r\n", "\n");
233 let mut token_handler = TokenHandler {
235 closing_tags: Vec::new(),
236 pending_exit_span: None,
238 pending_elems: Vec::new(),
244 token_handler.href_context.as_ref().map(|c| c.file_span).unwrap_or(DUMMY_SP),
247 .highlight(&mut |highlight| {
249 Highlight::Token { text, class } => {
250 // If we received a `ExitSpan` event and then have a non-compatible `Class`, we
251 // need to close the `<span>`.
252 let need_current_class_update = if let Some(pending) = token_handler.pending_exit_span &&
253 !can_merge(Some(pending), class, text) {
254 token_handler.handle_exit_span();
256 // If the two `Class` are different, time to flush the current content and start
258 } else if !can_merge(token_handler.current_class, class, text) {
259 token_handler.write_pending_elems(token_handler.current_class);
262 token_handler.current_class.is_none()
265 if need_current_class_update {
266 token_handler.current_class = class.map(Class::dummy);
268 token_handler.pending_elems.push((text, class));
270 Highlight::EnterSpan { class } => {
271 let mut should_add = true;
272 if let Some(pending_exit_span) = token_handler.pending_exit_span {
273 if class.is_equal_to(pending_exit_span) {
276 token_handler.handle_exit_span();
279 // We flush everything just in case...
280 if token_handler.write_pending_elems(token_handler.current_class) {
281 token_handler.current_class = None;
285 let closing_tag = enter_span(token_handler.out, class, &token_handler.href_context);
286 token_handler.closing_tags.push((closing_tag, class));
289 token_handler.current_class = None;
290 token_handler.pending_exit_span = None;
292 Highlight::ExitSpan => {
293 token_handler.current_class = None;
294 token_handler.pending_exit_span =
295 Some(token_handler.closing_tags.last().as_ref().expect("ExitSpan without EnterSpan").1);
301 fn write_footer(out: &mut Buffer, playground_button: Option<&str>) {
302 writeln!(out, "</code></pre>{}</div>", playground_button.unwrap_or_default());
305 /// How a span of text is classified. Mostly corresponds to token kinds.
306 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
312 /// Keywords that do pointer/reference stuff.
320 /// `Ident` isn't rendered in the HTML but we still need it for the `Span` it contains.
326 Decoration(&'static str),
330 /// It is only looking at the variant, not the variant content.
332 /// It is used mostly to group multiple similar HTML elements into one `<span>` instead of
334 fn is_equal_to(self, other: Self) -> bool {
335 match (self, other) {
336 (Self::Self_(_), Self::Self_(_))
337 | (Self::Macro(_), Self::Macro(_))
338 | (Self::Ident(_), Self::Ident(_)) => true,
339 (Self::Decoration(c1), Self::Decoration(c2)) => c1 == c2,
344 /// If `self` contains a `Span`, it'll be replaced with `DUMMY_SP` to prevent creating links
345 /// on "empty content" (because of the attributes merge).
346 fn dummy(self) -> Self {
348 Self::Self_(_) => Self::Self_(DUMMY_SP),
349 Self::Macro(_) => Self::Macro(DUMMY_SP),
350 Self::Ident(_) => Self::Ident(DUMMY_SP),
355 /// Returns the css class expected by rustdoc for each `Class`.
356 fn as_html(self) -> &'static str {
358 Class::Comment => "comment",
359 Class::DocComment => "doccomment",
360 Class::Attribute => "attribute",
361 Class::KeyWord => "kw",
362 Class::RefKeyWord => "kw-2",
363 Class::Self_(_) => "self",
364 Class::Macro(_) => "macro",
365 Class::MacroNonTerminal => "macro-nonterminal",
366 Class::String => "string",
367 Class::Number => "number",
368 Class::Bool => "bool-val",
369 Class::Ident(_) => "",
370 Class::Lifetime => "lifetime",
371 Class::PreludeTy => "prelude-ty",
372 Class::PreludeVal => "prelude-val",
373 Class::QuestionMark => "question-mark",
374 Class::Decoration(kind) => kind,
378 /// In case this is an item which can be converted into a link to a definition, it'll contain
379 /// a "span" (a tuple representing `(lo, hi)` equivalent of `Span`).
380 fn get_span(self) -> Option<Span> {
382 Self::Ident(sp) | Self::Self_(sp) | Self::Macro(sp) => Some(sp),
388 | Self::MacroNonTerminal
396 | Self::Decoration(_) => None,
402 Token { text: &'a str, class: Option<Class> },
403 EnterSpan { class: Class },
407 struct TokenIter<'a> {
411 impl<'a> Iterator for TokenIter<'a> {
412 type Item = (TokenKind, &'a str);
413 fn next(&mut self) -> Option<(TokenKind, &'a str)> {
414 if self.src.is_empty() {
417 let token = rustc_lexer::first_token(self.src);
418 let (text, rest) = self.src.split_at(token.len as usize);
420 Some((token.kind, text))
424 /// Classifies into identifier class; returns `None` if this is a non-keyword identifier.
425 fn get_real_ident_class(text: &str, allow_path_keywords: bool) -> Option<Class> {
426 let ignore: &[&str] =
427 if allow_path_keywords { &["self", "Self", "super", "crate"] } else { &["self", "Self"] };
428 if ignore.iter().any(|k| *k == text) {
432 "ref" | "mut" => Class::RefKeyWord,
433 "false" | "true" => Class::Bool,
434 _ if Symbol::intern(text).is_reserved(|| Edition::Edition2021) => Class::KeyWord,
439 /// This iterator comes from the same idea than "Peekable" except that it allows to "peek" more than
440 /// just the next item by using `peek_next`. The `peek` method always returns the next item after
441 /// the current one whereas `peek_next` will return the next item after the last one peeked.
443 /// You can use both `peek` and `peek_next` at the same time without problem.
444 struct PeekIter<'a> {
445 stored: VecDeque<(TokenKind, &'a str)>,
446 /// This position is reinitialized when using `next`. It is used in `peek_next`.
451 impl<'a> PeekIter<'a> {
452 fn new(iter: TokenIter<'a>) -> Self {
453 Self { stored: VecDeque::new(), peek_pos: 0, iter }
455 /// Returns the next item after the current one. It doesn't interfere with `peek_next` output.
456 fn peek(&mut self) -> Option<&(TokenKind, &'a str)> {
457 if self.stored.is_empty() {
458 if let Some(next) = self.iter.next() {
459 self.stored.push_back(next);
464 /// Returns the next item after the last one peeked. It doesn't interfere with `peek` output.
465 fn peek_next(&mut self) -> Option<&(TokenKind, &'a str)> {
467 if self.peek_pos - 1 < self.stored.len() {
468 self.stored.get(self.peek_pos - 1)
469 } else if let Some(next) = self.iter.next() {
470 self.stored.push_back(next);
478 impl<'a> Iterator for PeekIter<'a> {
479 type Item = (TokenKind, &'a str);
480 fn next(&mut self) -> Option<Self::Item> {
482 if let Some(first) = self.stored.pop_front() { Some(first) } else { self.iter.next() }
486 /// Custom spans inserted into the source. Eg --scrape-examples uses this to highlight function calls
488 starts: Vec<(u32, &'static str)>,
493 fn new(info: DecorationInfo) -> Self {
494 // Extract tuples (start, end, kind) into separate sequences of (start, kind) and (end).
495 let (mut starts, mut ends): (Vec<_>, Vec<_>) = info
498 .flat_map(|(kind, ranges)| ranges.into_iter().map(move |(lo, hi)| ((lo, kind), hi)))
501 // Sort the sequences in document order.
502 starts.sort_by_key(|(lo, _)| *lo);
505 Decorations { starts, ends }
509 /// Processes program tokens, classifying strings of text by highlighting
510 /// category (`Class`).
511 struct Classifier<'a> {
512 tokens: PeekIter<'a>,
515 in_macro_nonterminal: bool,
519 decorations: Option<Decorations>,
522 impl<'a> Classifier<'a> {
523 /// Takes as argument the source code to HTML-ify, the rust edition to use and the source code
524 /// file span which will be used later on by the `span_correspondance_map`.
525 fn new(src: &str, file_span: Span, decoration_info: Option<DecorationInfo>) -> Classifier<'_> {
526 let tokens = PeekIter::new(TokenIter { src });
527 let decorations = decoration_info.map(Decorations::new);
532 in_macro_nonterminal: false,
540 /// Convenient wrapper to create a [`Span`] from a position in the file.
541 fn new_span(&self, lo: u32, text: &str) -> Span {
542 let hi = lo + text.len() as u32;
543 let file_lo = self.file_span.lo();
544 self.file_span.with_lo(file_lo + BytePos(lo)).with_hi(file_lo + BytePos(hi))
547 /// Concatenate colons and idents as one when possible.
548 fn get_full_ident_path(&mut self) -> Vec<(TokenKind, usize, usize)> {
549 let start = self.byte_pos as usize;
551 let mut has_ident = false;
555 while let Some((TokenKind::Colon, _)) = self.tokens.peek() {
559 // Ident path can start with "::" but if we already have content in the ident path,
560 // the "::" is mandatory.
561 if has_ident && nb == 0 {
562 return vec![(TokenKind::Ident, start, pos)];
563 } else if nb != 0 && nb != 2 {
565 return vec![(TokenKind::Ident, start, pos), (TokenKind::Colon, pos, pos + nb)];
567 return vec![(TokenKind::Colon, start, pos + nb)];
571 if let Some((None, text)) = self.tokens.peek().map(|(token, text)| {
572 if *token == TokenKind::Ident {
573 let class = get_real_ident_class(text, true);
576 // Doesn't matter which Class we put in here...
577 (Some(Class::Comment), text)
580 // We only "add" the colon if there is an ident behind.
581 pos += text.len() + nb;
584 } else if nb > 0 && has_ident {
585 return vec![(TokenKind::Ident, start, pos), (TokenKind::Colon, pos, pos + nb)];
587 return vec![(TokenKind::Colon, start, start + nb)];
588 } else if has_ident {
589 return vec![(TokenKind::Ident, start, pos)];
596 /// Wraps the tokens iteration to ensure that the `byte_pos` is always correct.
598 /// It returns the token's kind, the token as a string and its byte position in the source
600 fn next(&mut self) -> Option<(TokenKind, &'a str, u32)> {
601 if let Some((kind, text)) = self.tokens.next() {
602 let before = self.byte_pos;
603 self.byte_pos += text.len() as u32;
604 Some((kind, text, before))
610 /// Exhausts the `Classifier` writing the output into `sink`.
612 /// The general structure for this method is to iterate over each token,
613 /// possibly giving it an HTML span with a class specifying what flavor of
615 fn highlight(mut self, sink: &mut dyn FnMut(Highlight<'a>)) {
617 if let Some(decs) = self.decorations.as_mut() {
618 let byte_pos = self.byte_pos;
619 let n_starts = decs.starts.iter().filter(|(i, _)| byte_pos >= *i).count();
620 for (_, kind) in decs.starts.drain(0..n_starts) {
621 sink(Highlight::EnterSpan { class: Class::Decoration(kind) });
624 let n_ends = decs.ends.iter().filter(|i| byte_pos >= **i).count();
625 for _ in decs.ends.drain(0..n_ends) {
626 sink(Highlight::ExitSpan);
633 .map(|t| matches!(t.0, TokenKind::Colon | TokenKind::Ident))
636 let tokens = self.get_full_ident_path();
637 for (token, start, end) in &tokens {
638 let text = &self.src[*start..*end];
639 self.advance(*token, text, sink, *start as u32);
640 self.byte_pos += text.len() as u32;
642 if !tokens.is_empty() {
646 if let Some((token, text, before)) = self.next() {
647 self.advance(token, text, sink, before);
654 /// Single step of highlighting. This will classify `token`, but maybe also a couple of
655 /// following ones as well.
657 /// `before` is the position of the given token in the `source` string and is used as "lo" byte
658 /// in case we want to try to generate a link for this token using the
659 /// `span_correspondance_map`.
664 sink: &mut dyn FnMut(Highlight<'a>),
667 let lookahead = self.peek();
668 let no_highlight = |sink: &mut dyn FnMut(_)| sink(Highlight::Token { text, class: None });
669 let class = match token {
670 TokenKind::Whitespace => return no_highlight(sink),
671 TokenKind::LineComment { doc_style } | TokenKind::BlockComment { doc_style, .. } => {
672 if doc_style.is_some() {
678 // Consider this as part of a macro invocation if there was a
679 // leading identifier.
680 TokenKind::Bang if self.in_macro => {
681 self.in_macro = false;
682 sink(Highlight::Token { text, class: None });
683 sink(Highlight::ExitSpan);
687 // Assume that '&' or '*' is the reference or dereference operator
688 // or a reference or pointer type. Unless, of course, it looks like
689 // a logical and or a multiplication operator: `&&` or `* `.
690 TokenKind::Star => match self.tokens.peek() {
691 Some((TokenKind::Whitespace, _)) => return no_highlight(sink),
692 Some((TokenKind::Ident, "mut")) => {
694 sink(Highlight::Token { text: "*mut", class: Some(Class::RefKeyWord) });
697 Some((TokenKind::Ident, "const")) => {
699 sink(Highlight::Token { text: "*const", class: Some(Class::RefKeyWord) });
702 _ => Class::RefKeyWord,
704 TokenKind::And => match self.tokens.peek() {
705 Some((TokenKind::And, _)) => {
707 sink(Highlight::Token { text: "&&", class: None });
710 Some((TokenKind::Eq, _)) => {
712 sink(Highlight::Token { text: "&=", class: None });
715 Some((TokenKind::Whitespace, _)) => return no_highlight(sink),
716 Some((TokenKind::Ident, "mut")) => {
718 sink(Highlight::Token { text: "&mut", class: Some(Class::RefKeyWord) });
721 _ => Class::RefKeyWord,
724 // These can either be operators, or arrows.
725 TokenKind::Eq => match lookahead {
726 Some(TokenKind::Eq) => {
728 sink(Highlight::Token { text: "==", class: None });
731 Some(TokenKind::Gt) => {
733 sink(Highlight::Token { text: "=>", class: None });
736 _ => return no_highlight(sink),
738 TokenKind::Minus if lookahead == Some(TokenKind::Gt) => {
740 sink(Highlight::Token { text: "->", class: None });
753 | TokenKind::Gt => return no_highlight(sink),
755 // Miscellaneous, no highlighting.
759 | TokenKind::OpenParen
760 | TokenKind::CloseParen
761 | TokenKind::OpenBrace
762 | TokenKind::CloseBrace
763 | TokenKind::OpenBracket
767 | TokenKind::Unknown => return no_highlight(sink),
769 TokenKind::Question => Class::QuestionMark,
771 TokenKind::Dollar => match lookahead {
772 Some(TokenKind::Ident) => {
773 self.in_macro_nonterminal = true;
774 Class::MacroNonTerminal
776 _ => return no_highlight(sink),
779 // This might be the start of an attribute. We're going to want to
780 // continue highlighting it as an attribute until the ending ']' is
781 // seen, so skip out early. Down below we terminate the attribute
782 // span when we see the ']'.
783 TokenKind::Pound => {
785 // Case 1: #![inner_attribute]
786 Some(TokenKind::Bang) => {
788 if let Some(TokenKind::OpenBracket) = self.peek() {
789 self.in_attribute = true;
790 sink(Highlight::EnterSpan { class: Class::Attribute });
792 sink(Highlight::Token { text: "#", class: None });
793 sink(Highlight::Token { text: "!", class: None });
796 // Case 2: #[outer_attribute]
797 Some(TokenKind::OpenBracket) => {
798 self.in_attribute = true;
799 sink(Highlight::EnterSpan { class: Class::Attribute });
803 return no_highlight(sink);
805 TokenKind::CloseBracket => {
806 if self.in_attribute {
807 self.in_attribute = false;
808 sink(Highlight::Token { text: "]", class: None });
809 sink(Highlight::ExitSpan);
812 return no_highlight(sink);
814 TokenKind::Literal { kind, .. } => match kind {
816 LiteralKind::Byte { .. }
817 | LiteralKind::Char { .. }
818 | LiteralKind::Str { .. }
819 | LiteralKind::ByteStr { .. }
820 | LiteralKind::RawStr { .. }
821 | LiteralKind::RawByteStr { .. } => Class::String,
823 LiteralKind::Float { .. } | LiteralKind::Int { .. } => Class::Number,
825 TokenKind::Ident | TokenKind::RawIdent if lookahead == Some(TokenKind::Bang) => {
826 self.in_macro = true;
827 sink(Highlight::EnterSpan { class: Class::Macro(self.new_span(before, text)) });
828 sink(Highlight::Token { text, class: None });
831 TokenKind::Ident => match get_real_ident_class(text, false) {
833 "Option" | "Result" => Class::PreludeTy,
834 "Some" | "None" | "Ok" | "Err" => Class::PreludeVal,
835 // "union" is a weak keyword and is only considered as a keyword when declaring
837 "union" if self.check_if_is_union_keyword() => Class::KeyWord,
838 _ if self.in_macro_nonterminal => {
839 self.in_macro_nonterminal = false;
840 Class::MacroNonTerminal
842 "self" | "Self" => Class::Self_(self.new_span(before, text)),
843 _ => Class::Ident(self.new_span(before, text)),
847 TokenKind::RawIdent | TokenKind::UnknownPrefix | TokenKind::InvalidIdent => {
848 Class::Ident(self.new_span(before, text))
850 TokenKind::Lifetime { .. } => Class::Lifetime,
852 // Anything that didn't return above is the simple case where we the
853 // class just spans a single token, so we can use the `string` method.
854 sink(Highlight::Token { text, class: Some(class) });
857 fn peek(&mut self) -> Option<TokenKind> {
858 self.tokens.peek().map(|(token_kind, _text)| *token_kind)
861 fn check_if_is_union_keyword(&mut self) -> bool {
862 while let Some(kind) = self.tokens.peek_next().map(|(token_kind, _text)| token_kind) {
863 if *kind == TokenKind::Whitespace {
866 return *kind == TokenKind::Ident;
872 /// Called when we start processing a span of text that should be highlighted.
873 /// The `Class` argument specifies how it should be highlighted.
877 href_context: &Option<HrefContext<'_, '_, '_>>,
879 string_without_closing_tag(out, "", Some(klass), href_context, true).expect(
880 "internal error: enter_span was called with Some(klass) but did not return a \
885 /// Called at the end of a span of highlighted text.
886 fn exit_span(out: &mut Buffer, closing_tag: &str) {
887 out.write_str(closing_tag);
890 /// Called for a span of text. If the text should be highlighted differently
891 /// from the surrounding text, then the `Class` argument will be a value other
894 /// The following sequences of callbacks are equivalent:
896 /// enter_span(Foo), string("text", None), exit_span()
897 /// string("text", Foo)
900 /// The latter can be thought of as a shorthand for the former, which is more
903 /// Note that if `context` is not `None` and that the given `klass` contains a `Span`, the function
904 /// will then try to find this `span` in the `span_correspondance_map`. If found, it'll then
905 /// generate a link for this element (which corresponds to where its definition is located).
906 fn string<T: Display>(
909 klass: Option<Class>,
910 href_context: &Option<HrefContext<'_, '_, '_>>,
913 if let Some(closing_tag) = string_without_closing_tag(out, text, klass, href_context, open_tag)
915 out.write_str(closing_tag);
919 /// This function writes `text` into `out` with some modifications depending on `klass`:
921 /// * If `klass` is `None`, `text` is written into `out` with no modification.
922 /// * If `klass` is `Some` but `klass.get_span()` is `None`, it writes the text wrapped in a
923 /// `<span>` with the provided `klass`.
924 /// * If `klass` is `Some` and has a [`rustc_span::Span`], it then tries to generate a link (`<a>`
925 /// element) by retrieving the link information from the `span_correspondance_map` that was filled
926 /// in `span_map.rs::collect_spans_and_sources`. If it cannot retrieve the information, then it's
927 /// the same as the second point (`klass` is `Some` but doesn't have a [`rustc_span::Span`]).
928 fn string_without_closing_tag<T: Display>(
931 klass: Option<Class>,
932 href_context: &Option<HrefContext<'_, '_, '_>>,
934 ) -> Option<&'static str> {
935 let Some(klass) = klass
937 write!(out, "{}", text);
940 let Some(def_span) = klass.get_span()
943 write!(out, "{}", text);
946 write!(out, "<span class=\"{}\">{}", klass.as_html(), text);
947 return Some("</span>");
950 let mut text_s = text.to_string();
951 if text_s.contains("::") {
952 text_s = text_s.split("::").intersperse("::").fold(String::new(), |mut path, t| {
954 "self" | "Self" => write!(
956 "<span class=\"{}\">{}</span>",
957 Class::Self_(DUMMY_SP).as_html(),
960 "crate" | "super" => {
961 write!(&mut path, "<span class=\"{}\">{}</span>", Class::KeyWord.as_html(), t)
963 t => write!(&mut path, "{}", t),
965 .expect("Failed to build source HTML path");
970 if let Some(href_context) = href_context {
972 href_context.context.shared.span_correspondance_map.get(&def_span).and_then(|href| {
973 let context = href_context.context;
974 // FIXME: later on, it'd be nice to provide two links (if possible) for all items:
975 // one to the documentation page and one to the source definition.
976 // FIXME: currently, external items only generate a link to their documentation,
977 // a link to their definition can be generated using this:
978 // https://github.com/rust-lang/rust/blob/60f1a2fc4b535ead9c85ce085fdce49b1b097531/src/librustdoc/html/render/context.rs#L315-L338
980 LinkFromSrc::Local(span) => context
981 .href_from_span(*span, true)
982 .map(|s| format!("{}{}", href_context.root_path, s)),
983 LinkFromSrc::External(def_id) => {
984 format::href_with_root_path(*def_id, context, Some(href_context.root_path))
986 .map(|(url, _, _)| url)
988 LinkFromSrc::Primitive(prim) => format::href_with_root_path(
989 PrimitiveType::primitive_locations(context.tcx())[prim],
991 Some(href_context.root_path),
994 .map(|(url, _, _)| url),
999 // We're already inside an element which has the same klass, no need to give it
1001 write!(out, "<a href=\"{}\">{}", href, text_s);
1003 let klass_s = klass.as_html();
1004 if klass_s.is_empty() {
1005 write!(out, "<a href=\"{}\">{}", href, text_s);
1007 write!(out, "<a class=\"{}\" href=\"{}\">{}", klass_s, href, text_s);
1010 return Some("</a>");
1014 write!(out, "{}", text_s);
1017 let klass_s = klass.as_html();
1018 if klass_s.is_empty() {
1019 write!(out, "{}", text_s);
1022 write!(out, "<span class=\"{}\">{}", klass_s, text_s);