src/librustdoc/html/markdown.rs

   1 //! Markdown formatting for rustdoc.
   2 //!
   3 //! This module implements markdown formatting through the pulldown-cmark library.
   4 //!
   5 //! ```
   6 //! #![feature(rustc_private)]
   7 //!
   8 //! extern crate rustc_span;
   9 //!
  10 //! use rustc_span::edition::Edition;
  11 //! use rustdoc::html::markdown::{IdMap, Markdown, ErrorCodes};
  12 //!
  13 //! let s = "My *markdown* _text_";
  14 //! let mut id_map = IdMap::new();
  15 //! let md = Markdown(s, &[], &mut id_map, ErrorCodes::Yes, Edition::Edition2015, &None);
  16 //! let html = md.to_string();
  17 //! // ... something using html
  18 //! ```
  19
  20 #![allow(non_camel_case_types)]
  21
  22 use rustc_data_structures::fx::FxHashMap;
  23 use rustc_span::edition::Edition;
  24 use std::borrow::Cow;
  25 use std::cell::RefCell;
  26 use std::collections::VecDeque;
  27 use std::default::Default;
  28 use std::fmt::Write;
  29 use std::ops::Range;
  30 use std::str;
  31
  32 use crate::html::highlight;
  33 use crate::html::toc::TocBuilder;
  34 use crate::test;
  35
  36 use pulldown_cmark::{html, CodeBlockKind, CowStr, Event, Options, Parser, Tag};
  37
  38 #[cfg(test)]
  39 mod tests;
  40
  41 fn opts() -> Options {
  42     Options::ENABLE_TABLES | Options::ENABLE_FOOTNOTES
  43 }
  44
  45 /// When `to_string` is called, this struct will emit the HTML corresponding to
  46 /// the rendered version of the contained markdown string.
  47 pub struct Markdown<'a>(
  48     pub &'a str,
  49     /// A list of link replacements.
  50     pub &'a [(String, String)],
  51     /// The current list of used header IDs.
  52     pub &'a mut IdMap,
  53     /// Whether to allow the use of explicit error codes in doctest lang strings.
  54     pub ErrorCodes,
  55     /// Default edition to use when parsing doctests (to add a `fn main`).
  56     pub Edition,
  57     pub &'a Option<Playground>,
  58 );
  59 /// A tuple struct like `Markdown` that renders the markdown with a table of contents.
  60 pub struct MarkdownWithToc<'a>(
  61     pub &'a str,
  62     pub &'a mut IdMap,
  63     pub ErrorCodes,
  64     pub Edition,
  65     pub &'a Option<Playground>,
  66 );
  67 /// A tuple struct like `Markdown` that renders the markdown escaping HTML tags.
  68 pub struct MarkdownHtml<'a>(
  69     pub &'a str,
  70     pub &'a mut IdMap,
  71     pub ErrorCodes,
  72     pub Edition,
  73     pub &'a Option<Playground>,
  74 );
  75 /// A tuple struct like `Markdown` that renders only the first paragraph.
  76 pub struct MarkdownSummaryLine<'a>(pub &'a str, pub &'a [(String, String)]);
  77
  78 #[derive(Copy, Clone, PartialEq, Debug)]
  79 pub enum ErrorCodes {
  80     Yes,
  81     No,
  82 }
  83
  84 impl ErrorCodes {
  85     pub fn from(b: bool) -> Self {
  86         match b {
  87             true => ErrorCodes::Yes,
  88             false => ErrorCodes::No,
  89         }
  90     }
  91
  92     pub fn as_bool(self) -> bool {
  93         match self {
  94             ErrorCodes::Yes => true,
  95             ErrorCodes::No => false,
  96         }
  97     }
  98 }
  99
 100 /// Controls whether a line will be hidden or shown in HTML output.
 101 ///
 102 /// All lines are used in documentation tests.
 103 enum Line<'a> {
 104     Hidden(&'a str),
 105     Shown(Cow<'a, str>),
 106 }
 107
 108 impl<'a> Line<'a> {
 109     fn for_html(self) -> Option<Cow<'a, str>> {
 110         match self {
 111             Line::Shown(l) => Some(l),
 112             Line::Hidden(_) => None,
 113         }
 114     }
 115
 116     fn for_code(self) -> Cow<'a, str> {
 117         match self {
 118             Line::Shown(l) => l,
 119             Line::Hidden(l) => Cow::Borrowed(l),
 120         }
 121     }
 122 }
 123
 124 // FIXME: There is a minor inconsistency here. For lines that start with ##, we
 125 // have no easy way of removing a potential single space after the hashes, which
 126 // is done in the single # case. This inconsistency seems okay, if non-ideal. In
 127 // order to fix it we'd have to iterate to find the first non-# character, and
 128 // then reallocate to remove it; which would make us return a String.
 129 fn map_line(s: &str) -> Line<'_> {
 130     let trimmed = s.trim();
 131     if trimmed.starts_with("##") {
 132         Line::Shown(Cow::Owned(s.replacen("##", "#", 1)))
 133     } else if trimmed.starts_with("# ") {
 134         // # text
 135         Line::Hidden(&trimmed[2..])
 136     } else if trimmed == "#" {
 137         // We cannot handle '#text' because it could be #[attr].
 138         Line::Hidden("")
 139     } else {
 140         Line::Shown(Cow::Borrowed(s))
 141     }
 142 }
 143
 144 /// Convert chars from a title for an id.
 145 ///
 146 /// "Hello, world!" -> "hello-world"
 147 fn slugify(c: char) -> Option<char> {
 148     if c.is_alphanumeric() || c == '-' || c == '_' {
 149         if c.is_ascii() { Some(c.to_ascii_lowercase()) } else { Some(c) }
 150     } else if c.is_whitespace() && c.is_ascii() {
 151         Some('-')
 152     } else {
 153         None
 154     }
 155 }
 156
 157 #[derive(Clone, Debug)]
 158 pub struct Playground {
 159     pub crate_name: Option<String>,
 160     pub url: String,
 161 }
 162
 163 /// Adds syntax highlighting and playground Run buttons to Rust code blocks.
 164 struct CodeBlocks<'p, 'a, I: Iterator<Item = Event<'a>>> {
 165     inner: I,
 166     check_error_codes: ErrorCodes,
 167     edition: Edition,
 168     // Information about the playground if a URL has been specified, containing an
 169     // optional crate name and the URL.
 170     playground: &'p Option<Playground>,
 171 }
 172
 173 impl<'p, 'a, I: Iterator<Item = Event<'a>>> CodeBlocks<'p, 'a, I> {
 174     fn new(
 175         iter: I,
 176         error_codes: ErrorCodes,
 177         edition: Edition,
 178         playground: &'p Option<Playground>,
 179     ) -> Self {
 180         CodeBlocks { inner: iter, check_error_codes: error_codes, edition, playground }
 181     }
 182 }
 183
 184 impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
 185     type Item = Event<'a>;
 186
 187     fn next(&mut self) -> Option<Self::Item> {
 188         let event = self.inner.next();
 189         let compile_fail;
 190         let ignore;
 191         let edition;
 192         if let Some(Event::Start(Tag::CodeBlock(kind))) = event {
 193             let parse_result = match kind {
 194                 CodeBlockKind::Fenced(ref lang) => {
 195                     LangString::parse(&lang, self.check_error_codes, false)
 196                 }
 197                 CodeBlockKind::Indented => LangString::all_false(),
 198             };
 199             if !parse_result.rust {
 200                 return Some(Event::Start(Tag::CodeBlock(kind)));
 201             }
 202             compile_fail = parse_result.compile_fail;
 203             ignore = parse_result.ignore;
 204             edition = parse_result.edition;
 205         } else {
 206             return event;
 207         }
 208
 209         let explicit_edition = edition.is_some();
 210         let edition = edition.unwrap_or(self.edition);
 211
 212         let mut origtext = String::new();
 213         for event in &mut self.inner {
 214             match event {
 215                 Event::End(Tag::CodeBlock(..)) => break,
 216                 Event::Text(ref s) => {
 217                     origtext.push_str(s);
 218                 }
 219                 _ => {}
 220             }
 221         }
 222         let lines = origtext.lines().filter_map(|l| map_line(l).for_html());
 223         let text = lines.collect::<Vec<Cow<'_, str>>>().join("\n");
 224         // insert newline to clearly separate it from the
 225         // previous block so we can shorten the html output
 226         let mut s = String::from("\n");
 227         let playground_button = self.playground.as_ref().and_then(|playground| {
 228             let krate = &playground.crate_name;
 229             let url = &playground.url;
 230             if url.is_empty() {
 231                 return None;
 232             }
 233             let test = origtext
 234                 .lines()
 235                 .map(|l| map_line(l).for_code())
 236                 .collect::<Vec<Cow<'_, str>>>()
 237                 .join("\n");
 238             let krate = krate.as_ref().map(|s| &**s);
 239             let (test, _) = test::make_test(&test, krate, false, &Default::default(), edition);
 240             let channel = if test.contains("#![feature(") { "&amp;version=nightly" } else { "" };
 241
 242             let edition_string = format!("&amp;edition={}", edition);
 243
 244             // These characters don't need to be escaped in a URI.
 245             // FIXME: use a library function for percent encoding.
 246             fn dont_escape(c: u8) -> bool {
 247                 (b'a' <= c && c <= b'z')
 248                     || (b'A' <= c && c <= b'Z')
 249                     || (b'0' <= c && c <= b'9')
 250                     || c == b'-'
 251                     || c == b'_'
 252                     || c == b'.'
 253                     || c == b'~'
 254                     || c == b'!'
 255                     || c == b'\''
 256                     || c == b'('
 257                     || c == b')'
 258                     || c == b'*'
 259             }
 260             let mut test_escaped = String::new();
 261             for b in test.bytes() {
 262                 if dont_escape(b) {
 263                     test_escaped.push(char::from(b));
 264                 } else {
 265                     write!(test_escaped, "%{:02X}", b).unwrap();
 266                 }
 267             }
 268             Some(format!(
 269                 r#"<a class="test-arrow" target="_blank" href="{}?code={}{}{}">Run</a>"#,
 270                 url, test_escaped, channel, edition_string
 271             ))
 272         });
 273
 274         let tooltip = if ignore != Ignore::None {
 275             Some(("This example is not tested".to_owned(), "ignore"))
 276         } else if compile_fail {
 277             Some(("This example deliberately fails to compile".to_owned(), "compile_fail"))
 278         } else if explicit_edition {
 279             Some((format!("This code runs with edition {}", edition), "edition"))
 280         } else {
 281             None
 282         };
 283
 284         if let Some((s1, s2)) = tooltip {
 285             s.push_str(&highlight::render_with_highlighting(
 286                 &text,
 287                 Some(&format!(
 288                     "rust-example-rendered{}",
 289                     if ignore != Ignore::None {
 290                         " ignore"
 291                     } else if compile_fail {
 292                         " compile_fail"
 293                     } else if explicit_edition {
 294                         " edition "
 295                     } else {
 296                         ""
 297                     }
 298                 )),
 299                 playground_button.as_deref(),
 300                 Some((s1.as_str(), s2)),
 301             ));
 302             Some(Event::Html(s.into()))
 303         } else {
 304             s.push_str(&highlight::render_with_highlighting(
 305                 &text,
 306                 Some(&format!(
 307                     "rust-example-rendered{}",
 308                     if ignore != Ignore::None {
 309                         " ignore"
 310                     } else if compile_fail {
 311                         " compile_fail"
 312                     } else if explicit_edition {
 313                         " edition "
 314                     } else {
 315                         ""
 316                     }
 317                 )),
 318                 playground_button.as_deref(),
 319                 None,
 320             ));
 321             Some(Event::Html(s.into()))
 322         }
 323     }
 324 }
 325
 326 /// Make headings links with anchor IDs and build up TOC.
 327 struct LinkReplacer<'a, 'b, I: Iterator<Item = Event<'a>>> {
 328     inner: I,
 329     links: &'b [(String, String)],
 330 }
 331
 332 impl<'a, 'b, I: Iterator<Item = Event<'a>>> LinkReplacer<'a, 'b, I> {
 333     fn new(iter: I, links: &'b [(String, String)]) -> Self {
 334         LinkReplacer { inner: iter, links }
 335     }
 336 }
 337
 338 impl<'a, 'b, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, 'b, I> {
 339     type Item = Event<'a>;
 340
 341     fn next(&mut self) -> Option<Self::Item> {
 342         let event = self.inner.next();
 343         if let Some(Event::Start(Tag::Link(kind, dest, text))) = event {
 344             if let Some(&(_, ref replace)) = self.links.iter().find(|link| link.0 == *dest) {
 345                 Some(Event::Start(Tag::Link(kind, replace.to_owned().into(), text)))
 346             } else {
 347                 Some(Event::Start(Tag::Link(kind, dest, text)))
 348             }
 349         } else {
 350             event
 351         }
 352     }
 353 }
 354
 355 /// Make headings links with anchor IDs and build up TOC.
 356 struct HeadingLinks<'a, 'b, 'ids, I: Iterator<Item = Event<'a>>> {
 357     inner: I,
 358     toc: Option<&'b mut TocBuilder>,
 359     buf: VecDeque<Event<'a>>,
 360     id_map: &'ids mut IdMap,
 361 }
 362
 363 impl<'a, 'b, 'ids, I: Iterator<Item = Event<'a>>> HeadingLinks<'a, 'b, 'ids, I> {
 364     fn new(iter: I, toc: Option<&'b mut TocBuilder>, ids: &'ids mut IdMap) -> Self {
 365         HeadingLinks { inner: iter, toc, buf: VecDeque::new(), id_map: ids }
 366     }
 367 }
 368
 369 impl<'a, 'b, 'ids, I: Iterator<Item = Event<'a>>> Iterator for HeadingLinks<'a, 'b, 'ids, I> {
 370     type Item = Event<'a>;
 371
 372     fn next(&mut self) -> Option<Self::Item> {
 373         if let Some(e) = self.buf.pop_front() {
 374             return Some(e);
 375         }
 376
 377         let event = self.inner.next();
 378         if let Some(Event::Start(Tag::Heading(level))) = event {
 379             let mut id = String::new();
 380             for event in &mut self.inner {
 381                 match &event {
 382                     Event::End(Tag::Heading(..)) => break,
 383                     Event::Text(text) | Event::Code(text) => {
 384                         id.extend(text.chars().filter_map(slugify));
 385                     }
 386                     _ => {}
 387                 }
 388                 match event {
 389                     Event::Start(Tag::Link(_, _, _)) | Event::End(Tag::Link(..)) => {}
 390                     event => self.buf.push_back(event),
 391                 }
 392             }
 393             let id = self.id_map.derive(id);
 394
 395             if let Some(ref mut builder) = self.toc {
 396                 let mut html_header = String::new();
 397                 html::push_html(&mut html_header, self.buf.iter().cloned());
 398                 let sec = builder.push(level as u32, html_header, id.clone());
 399                 self.buf.push_front(Event::Html(format!("{} ", sec).into()));
 400             }
 401
 402             self.buf.push_back(Event::Html(format!("</a></h{}>", level).into()));
 403
 404             let start_tags = format!(
 405                 "<h{level} id=\"{id}\" class=\"section-header\">\
 406                     <a href=\"#{id}\">",
 407                 id = id,
 408                 level = level
 409             );
 410             return Some(Event::Html(start_tags.into()));
 411         }
 412         event
 413     }
 414 }
 415
 416 /// Extracts just the first paragraph.
 417 struct SummaryLine<'a, I: Iterator<Item = Event<'a>>> {
 418     inner: I,
 419     started: bool,
 420     depth: u32,
 421 }
 422
 423 impl<'a, I: Iterator<Item = Event<'a>>> SummaryLine<'a, I> {
 424     fn new(iter: I) -> Self {
 425         SummaryLine { inner: iter, started: false, depth: 0 }
 426     }
 427 }
 428
 429 fn check_if_allowed_tag(t: &Tag<'_>) -> bool {
 430     match *t {
 431         Tag::Paragraph
 432         | Tag::Item
 433         | Tag::Emphasis
 434         | Tag::Strong
 435         | Tag::Link(..)
 436         | Tag::BlockQuote => true,
 437         _ => false,
 438     }
 439 }
 440
 441 impl<'a, I: Iterator<Item = Event<'a>>> Iterator for SummaryLine<'a, I> {
 442     type Item = Event<'a>;
 443
 444     fn next(&mut self) -> Option<Self::Item> {
 445         if self.started && self.depth == 0 {
 446             return None;
 447         }
 448         if !self.started {
 449             self.started = true;
 450         }
 451         if let Some(event) = self.inner.next() {
 452             let mut is_start = true;
 453             let is_allowed_tag = match event {
 454                 Event::Start(Tag::CodeBlock(_)) | Event::End(Tag::CodeBlock(_)) => {
 455                     return None;
 456                 }
 457                 Event::Start(ref c) => {
 458                     self.depth += 1;
 459                     check_if_allowed_tag(c)
 460                 }
 461                 Event::End(ref c) => {
 462                     self.depth -= 1;
 463                     is_start = false;
 464                     check_if_allowed_tag(c)
 465                 }
 466                 _ => true,
 467             };
 468             return if !is_allowed_tag {
 469                 if is_start {
 470                     Some(Event::Start(Tag::Paragraph))
 471                 } else {
 472                     Some(Event::End(Tag::Paragraph))
 473                 }
 474             } else {
 475                 Some(event)
 476             };
 477         }
 478         None
 479     }
 480 }
 481
 482 /// Moves all footnote definitions to the end and add back links to the
 483 /// references.
 484 struct Footnotes<'a, I: Iterator<Item = Event<'a>>> {
 485     inner: I,
 486     footnotes: FxHashMap<String, (Vec<Event<'a>>, u16)>,
 487 }
 488
 489 impl<'a, I: Iterator<Item = Event<'a>>> Footnotes<'a, I> {
 490     fn new(iter: I) -> Self {
 491         Footnotes { inner: iter, footnotes: FxHashMap::default() }
 492     }
 493     fn get_entry(&mut self, key: &str) -> &mut (Vec<Event<'a>>, u16) {
 494         let new_id = self.footnotes.keys().count() + 1;
 495         let key = key.to_owned();
 496         self.footnotes.entry(key).or_insert((Vec::new(), new_id as u16))
 497     }
 498 }
 499
 500 impl<'a, I: Iterator<Item = Event<'a>>> Iterator for Footnotes<'a, I> {
 501     type Item = Event<'a>;
 502
 503     fn next(&mut self) -> Option<Self::Item> {
 504         loop {
 505             match self.inner.next() {
 506                 Some(Event::FootnoteReference(ref reference)) => {
 507                     let entry = self.get_entry(&reference);
 508                     let reference = format!(
 509                         "<sup id=\"fnref{0}\"><a href=\"#fn{0}\">{0}\
 510                                              </a></sup>",
 511                         (*entry).1
 512                     );
 513                     return Some(Event::Html(reference.into()));
 514                 }
 515                 Some(Event::Start(Tag::FootnoteDefinition(def))) => {
 516                     let mut content = Vec::new();
 517                     for event in &mut self.inner {
 518                         if let Event::End(Tag::FootnoteDefinition(..)) = event {
 519                             break;
 520                         }
 521                         content.push(event);
 522                     }
 523                     let entry = self.get_entry(&def);
 524                     (*entry).0 = content;
 525                 }
 526                 Some(e) => return Some(e),
 527                 None => {
 528                     if !self.footnotes.is_empty() {
 529                         let mut v: Vec<_> = self.footnotes.drain().map(|(_, x)| x).collect();
 530                         v.sort_by(|a, b| a.1.cmp(&b.1));
 531                         let mut ret = String::from("<div class=\"footnotes\"><hr><ol>");
 532                         for (mut content, id) in v {
 533                             write!(ret, "<li id=\"fn{}\">", id).unwrap();
 534                             let mut is_paragraph = false;
 535                             if let Some(&Event::End(Tag::Paragraph)) = content.last() {
 536                                 content.pop();
 537                                 is_paragraph = true;
 538                             }
 539                             html::push_html(&mut ret, content.into_iter());
 540                             write!(ret, "&nbsp;<a href=\"#fnref{}\" rev=\"footnote\">↩</a>", id)
 541                                 .unwrap();
 542                             if is_paragraph {
 543                                 ret.push_str("</p>");
 544                             }
 545                             ret.push_str("</li>");
 546                         }
 547                         ret.push_str("</ol></div>");
 548                         return Some(Event::Html(ret.into()));
 549                     } else {
 550                         return None;
 551                     }
 552                 }
 553             }
 554         }
 555     }
 556 }
 557
 558 pub fn find_testable_code<T: test::Tester>(
 559     doc: &str,
 560     tests: &mut T,
 561     error_codes: ErrorCodes,
 562     enable_per_target_ignores: bool,
 563 ) {
 564     let mut parser = Parser::new(doc).into_offset_iter();
 565     let mut prev_offset = 0;
 566     let mut nb_lines = 0;
 567     let mut register_header = None;
 568     while let Some((event, offset)) = parser.next() {
 569         match event {
 570             Event::Start(Tag::CodeBlock(kind)) => {
 571                 let block_info = match kind {
 572                     CodeBlockKind::Fenced(ref lang) => {
 573                         if lang.is_empty() {
 574                             LangString::all_false()
 575                         } else {
 576                             LangString::parse(lang, error_codes, enable_per_target_ignores)
 577                         }
 578                     }
 579                     CodeBlockKind::Indented => LangString::all_false(),
 580                 };
 581                 if !block_info.rust {
 582                     continue;
 583                 }
 584
 585                 let mut test_s = String::new();
 586
 587                 while let Some((Event::Text(s), _)) = parser.next() {
 588                     test_s.push_str(&s);
 589                 }
 590                 let text = test_s
 591                     .lines()
 592                     .map(|l| map_line(l).for_code())
 593                     .collect::<Vec<Cow<'_, str>>>()
 594                     .join("\n");
 595
 596                 nb_lines += doc[prev_offset..offset.start].lines().count();
 597                 let line = tests.get_line() + nb_lines + 1;
 598                 tests.add_test(text, block_info, line);
 599                 prev_offset = offset.start;
 600             }
 601             Event::Start(Tag::Heading(level)) => {
 602                 register_header = Some(level as u32);
 603             }
 604             Event::Text(ref s) if register_header.is_some() => {
 605                 let level = register_header.unwrap();
 606                 if s.is_empty() {
 607                     tests.register_header("", level);
 608                 } else {
 609                     tests.register_header(s, level);
 610                 }
 611                 register_header = None;
 612             }
 613             _ => {}
 614         }
 615     }
 616 }
 617
 618 #[derive(Eq, PartialEq, Clone, Debug)]
 619 pub struct LangString {
 620     original: String,
 621     pub should_panic: bool,
 622     pub no_run: bool,
 623     pub ignore: Ignore,
 624     pub rust: bool,
 625     pub test_harness: bool,
 626     pub compile_fail: bool,
 627     pub error_codes: Vec<String>,
 628     pub allow_fail: bool,
 629     pub edition: Option<Edition>,
 630 }
 631
 632 #[derive(Eq, PartialEq, Clone, Debug)]
 633 pub enum Ignore {
 634     All,
 635     None,
 636     Some(Vec<String>),
 637 }
 638
 639 impl LangString {
 640     fn all_false() -> LangString {
 641         LangString {
 642             original: String::new(),
 643             should_panic: false,
 644             no_run: false,
 645             ignore: Ignore::None,
 646             rust: true, // NB This used to be `notrust = false`
 647             test_harness: false,
 648             compile_fail: false,
 649             error_codes: Vec::new(),
 650             allow_fail: false,
 651             edition: None,
 652         }
 653     }
 654
 655     fn parse(
 656         string: &str,
 657         allow_error_code_check: ErrorCodes,
 658         enable_per_target_ignores: bool,
 659     ) -> LangString {
 660         let allow_error_code_check = allow_error_code_check.as_bool();
 661         let mut seen_rust_tags = false;
 662         let mut seen_other_tags = false;
 663         let mut data = LangString::all_false();
 664         let mut ignores = vec![];
 665
 666         data.original = string.to_owned();
 667         let tokens = string.split(|c: char| !(c == '_' || c == '-' || c.is_alphanumeric()));
 668
 669         for token in tokens {
 670             match token.trim() {
 671                 "" => {}
 672                 "should_panic" => {
 673                     data.should_panic = true;
 674                     seen_rust_tags = !seen_other_tags;
 675                 }
 676                 "no_run" => {
 677                     data.no_run = true;
 678                     seen_rust_tags = !seen_other_tags;
 679                 }
 680                 "ignore" => {
 681                     data.ignore = Ignore::All;
 682                     seen_rust_tags = !seen_other_tags;
 683                 }
 684                 x if x.starts_with("ignore-") => {
 685                     if enable_per_target_ignores {
 686                         ignores.push(x.trim_start_matches("ignore-").to_owned());
 687                         seen_rust_tags = !seen_other_tags;
 688                     }
 689                 }
 690                 "allow_fail" => {
 691                     data.allow_fail = true;
 692                     seen_rust_tags = !seen_other_tags;
 693                 }
 694                 "rust" => {
 695                     data.rust = true;
 696                     seen_rust_tags = true;
 697                 }
 698                 "test_harness" => {
 699                     data.test_harness = true;
 700                     seen_rust_tags = !seen_other_tags || seen_rust_tags;
 701                 }
 702                 "compile_fail" => {
 703                     data.compile_fail = true;
 704                     seen_rust_tags = !seen_other_tags || seen_rust_tags;
 705                     data.no_run = true;
 706                 }
 707                 x if x.starts_with("edition") => {
 708                     data.edition = x[7..].parse::<Edition>().ok();
 709                 }
 710                 x if allow_error_code_check && x.starts_with('E') && x.len() == 5 => {
 711                     if x[1..].parse::<u32>().is_ok() {
 712                         data.error_codes.push(x.to_owned());
 713                         seen_rust_tags = !seen_other_tags || seen_rust_tags;
 714                     } else {
 715                         seen_other_tags = true;
 716                     }
 717                 }
 718                 _ => seen_other_tags = true,
 719             }
 720         }
 721         // ignore-foo overrides ignore
 722         if !ignores.is_empty() {
 723             data.ignore = Ignore::Some(ignores);
 724         }
 725
 726         data.rust &= !seen_other_tags || seen_rust_tags;
 727
 728         data
 729     }
 730 }
 731
 732 impl Markdown<'_> {
 733     pub fn to_string(self) -> String {
 734         let Markdown(md, links, mut ids, codes, edition, playground) = self;
 735
 736         // This is actually common enough to special-case
 737         if md.is_empty() {
 738             return String::new();
 739         }
 740         let replacer = |_: &str, s: &str| {
 741             if let Some(&(_, ref replace)) = links.iter().find(|link| &*link.0 == s) {
 742                 Some((replace.clone(), s.to_owned()))
 743             } else {
 744                 None
 745             }
 746         };
 747
 748         let p = Parser::new_with_broken_link_callback(md, opts(), Some(&replacer));
 749
 750         let mut s = String::with_capacity(md.len() * 3 / 2);
 751
 752         let p = HeadingLinks::new(p, None, &mut ids);
 753         let p = LinkReplacer::new(p, links);
 754         let p = CodeBlocks::new(p, codes, edition, playground);
 755         let p = Footnotes::new(p);
 756         html::push_html(&mut s, p);
 757
 758         s
 759     }
 760 }
 761
 762 impl MarkdownWithToc<'_> {
 763     pub fn to_string(self) -> String {
 764         let MarkdownWithToc(md, mut ids, codes, edition, playground) = self;
 765
 766         let p = Parser::new_ext(md, opts());
 767
 768         let mut s = String::with_capacity(md.len() * 3 / 2);
 769
 770         let mut toc = TocBuilder::new();
 771
 772         {
 773             let p = HeadingLinks::new(p, Some(&mut toc), &mut ids);
 774             let p = CodeBlocks::new(p, codes, edition, playground);
 775             let p = Footnotes::new(p);
 776             html::push_html(&mut s, p);
 777         }
 778
 779         format!("<nav id=\"TOC\">{}</nav>{}", toc.into_toc().print(), s)
 780     }
 781 }
 782
 783 impl MarkdownHtml<'_> {
 784     pub fn to_string(self) -> String {
 785         let MarkdownHtml(md, mut ids, codes, edition, playground) = self;
 786
 787         // This is actually common enough to special-case
 788         if md.is_empty() {
 789             return String::new();
 790         }
 791         let p = Parser::new_ext(md, opts());
 792
 793         // Treat inline HTML as plain text.
 794         let p = p.map(|event| match event {
 795             Event::Html(text) => Event::Text(text),
 796             _ => event,
 797         });
 798
 799         let mut s = String::with_capacity(md.len() * 3 / 2);
 800
 801         let p = HeadingLinks::new(p, None, &mut ids);
 802         let p = CodeBlocks::new(p, codes, edition, playground);
 803         let p = Footnotes::new(p);
 804         html::push_html(&mut s, p);
 805
 806         s
 807     }
 808 }
 809
 810 impl MarkdownSummaryLine<'_> {
 811     pub fn to_string(self) -> String {
 812         let MarkdownSummaryLine(md, links) = self;
 813         // This is actually common enough to special-case
 814         if md.is_empty() {
 815             return String::new();
 816         }
 817
 818         let replacer = |_: &str, s: &str| {
 819             if let Some(&(_, ref replace)) = links.iter().find(|link| &*link.0 == s) {
 820                 Some((replace.clone(), s.to_owned()))
 821             } else {
 822                 None
 823             }
 824         };
 825
 826         let p = Parser::new_with_broken_link_callback(md, Options::empty(), Some(&replacer));
 827
 828         let mut s = String::new();
 829
 830         html::push_html(&mut s, LinkReplacer::new(SummaryLine::new(p), links));
 831
 832         s
 833     }
 834 }
 835
 836 pub fn plain_summary_line(md: &str) -> String {
 837     struct ParserWrapper<'a> {
 838         inner: Parser<'a>,
 839         is_in: isize,
 840         is_first: bool,
 841     }
 842
 843     impl<'a> Iterator for ParserWrapper<'a> {
 844         type Item = String;
 845
 846         fn next(&mut self) -> Option<String> {
 847             let next_event = self.inner.next()?;
 848             let (ret, is_in) = match next_event {
 849                 Event::Start(Tag::Paragraph) => (None, 1),
 850                 Event::Start(Tag::Heading(_)) => (None, 1),
 851                 Event::Code(code) => (Some(format!("`{}`", code)), 0),
 852                 Event::Text(ref s) if self.is_in > 0 => (Some(s.as_ref().to_owned()), 0),
 853                 Event::End(Tag::Paragraph | Tag::Heading(_)) => (None, -1),
 854                 _ => (None, 0),
 855             };
 856             if is_in > 0 || (is_in < 0 && self.is_in > 0) {
 857                 self.is_in += is_in;
 858             }
 859             if ret.is_some() {
 860                 self.is_first = false;
 861                 ret
 862             } else {
 863                 Some(String::new())
 864             }
 865         }
 866     }
 867     let mut s = String::with_capacity(md.len() * 3 / 2);
 868     let p = ParserWrapper { inner: Parser::new(md), is_in: 0, is_first: true };
 869     p.filter(|t| !t.is_empty()).for_each(|i| s.push_str(&i));
 870     s
 871 }
 872
 873 pub fn markdown_links(md: &str) -> Vec<(String, Option<Range<usize>>)> {
 874     if md.is_empty() {
 875         return vec![];
 876     }
 877
 878     let mut links = vec![];
 879     let shortcut_links = RefCell::new(vec![]);
 880
 881     {
 882         let locate = |s: &str| unsafe {
 883             let s_start = s.as_ptr();
 884             let s_end = s_start.add(s.len());
 885             let md_start = md.as_ptr();
 886             let md_end = md_start.add(md.len());
 887             if md_start <= s_start && s_end <= md_end {
 888                 let start = s_start.offset_from(md_start) as usize;
 889                 let end = s_end.offset_from(md_start) as usize;
 890                 Some(start..end)
 891             } else {
 892                 None
 893             }
 894         };
 895
 896         let push = |_: &str, s: &str| {
 897             shortcut_links.borrow_mut().push((s.to_owned(), locate(s)));
 898             None
 899         };
 900         let p = Parser::new_with_broken_link_callback(md, opts(), Some(&push));
 901
 902         // There's no need to thread an IdMap through to here because
 903         // the IDs generated aren't going to be emitted anywhere.
 904         let mut ids = IdMap::new();
 905         let iter = Footnotes::new(HeadingLinks::new(p, None, &mut ids));
 906
 907         for ev in iter {
 908             if let Event::Start(Tag::Link(_, dest, _)) = ev {
 909                 debug!("found link: {}", dest);
 910                 links.push(match dest {
 911                     CowStr::Borrowed(s) => (s.to_owned(), locate(s)),
 912                     s @ (CowStr::Boxed(..) | CowStr::Inlined(..)) => (s.into_string(), None),
 913                 });
 914             }
 915         }
 916     }
 917
 918     let mut shortcut_links = shortcut_links.into_inner();
 919     links.extend(shortcut_links.drain(..));
 920
 921     links
 922 }
 923
 924 #[derive(Debug)]
 925 crate struct RustCodeBlock {
 926     /// The range in the markdown that the code block occupies. Note that this includes the fences
 927     /// for fenced code blocks.
 928     pub range: Range<usize>,
 929     /// The range in the markdown that the code within the code block occupies.
 930     pub code: Range<usize>,
 931     pub is_fenced: bool,
 932     pub syntax: Option<String>,
 933 }
 934
 935 /// Returns a range of bytes for each code block in the markdown that is tagged as `rust` or
 936 /// untagged (and assumed to be rust).
 937 crate fn rust_code_blocks(md: &str) -> Vec<RustCodeBlock> {
 938     let mut code_blocks = vec![];
 939
 940     if md.is_empty() {
 941         return code_blocks;
 942     }
 943
 944     let mut p = Parser::new_ext(md, opts()).into_offset_iter();
 945
 946     while let Some((event, offset)) = p.next() {
 947         if let Event::Start(Tag::CodeBlock(syntax)) = event {
 948             let (syntax, code_start, code_end, range, is_fenced) = match syntax {
 949                 CodeBlockKind::Fenced(syntax) => {
 950                     let syntax = syntax.as_ref();
 951                     let lang_string = if syntax.is_empty() {
 952                         LangString::all_false()
 953                     } else {
 954                         LangString::parse(&*syntax, ErrorCodes::Yes, false)
 955                     };
 956                     if !lang_string.rust {
 957                         continue;
 958                     }
 959                     let syntax = if syntax.is_empty() { None } else { Some(syntax.to_owned()) };
 960                     let (code_start, mut code_end) = match p.next() {
 961                         Some((Event::Text(_), offset)) => (offset.start, offset.end),
 962                         Some((_, sub_offset)) => {
 963                             let code = Range { start: sub_offset.start, end: sub_offset.start };
 964                             code_blocks.push(RustCodeBlock {
 965                                 is_fenced: true,
 966                                 range: offset,
 967                                 code,
 968                                 syntax,
 969                             });
 970                             continue;
 971                         }
 972                         None => {
 973                             let code = Range { start: offset.end, end: offset.end };
 974                             code_blocks.push(RustCodeBlock {
 975                                 is_fenced: true,
 976                                 range: offset,
 977                                 code,
 978                                 syntax,
 979                             });
 980                             continue;
 981                         }
 982                     };
 983                     while let Some((Event::Text(_), offset)) = p.next() {
 984                         code_end = offset.end;
 985                     }
 986                     (syntax, code_start, code_end, offset, true)
 987                 }
 988                 CodeBlockKind::Indented => {
 989                     // The ending of the offset goes too far sometime so we reduce it by one in
 990                     // these cases.
 991                     if offset.end > offset.start && md.get(offset.end..=offset.end) == Some(&"\n") {
 992                         (
 993                             None,
 994                             offset.start,
 995                             offset.end,
 996                             Range { start: offset.start, end: offset.end - 1 },
 997                             false,
 998                         )
 999                     } else {
1000                         (None, offset.start, offset.end, offset, false)
1001                     }
1002                 }
1003             };
1004
1005             code_blocks.push(RustCodeBlock {
1006                 is_fenced,
1007                 range,
1008                 code: Range { start: code_start, end: code_end },
1009                 syntax,
1010             });
1011         }
1012     }
1013
1014     code_blocks
1015 }
1016
1017 #[derive(Clone, Default, Debug)]
1018 pub struct IdMap {
1019     map: FxHashMap<String, usize>,
1020 }
1021
1022 impl IdMap {
1023     pub fn new() -> Self {
1024         IdMap::default()
1025     }
1026
1027     pub fn populate<I: IntoIterator<Item = String>>(&mut self, ids: I) {
1028         for id in ids {
1029             let _ = self.derive(id);
1030         }
1031     }
1032
1033     pub fn reset(&mut self) {
1034         self.map = FxHashMap::default();
1035     }
1036
1037     pub fn derive(&mut self, candidate: String) -> String {
1038         let id = match self.map.get_mut(&candidate) {
1039             None => candidate,
1040             Some(a) => {
1041                 let id = format!("{}-{}", candidate, *a);
1042                 *a += 1;
1043                 id
1044             }
1045         };
1046
1047         self.map.insert(id.clone(), 1);
1048         id
1049     }
1050 }