1 //! Extracts, resolves and rewrites links and intra-doc links in markdown documentation.
8 use pulldown_cmark::{BrokenLink, CowStr, Event, InlineStr, LinkType, Options, Parser, Tag};
9 use pulldown_cmark_to_cmark::{cmark_resume_with_options, Options as CMarkOptions};
13 use hir::{db::HirDatabase, Adt, AsAssocItem, AssocItem, AssocItemContainer, HasAttrs};
15 base_db::{CrateOrigin, LangCrateOrigin, SourceDatabase},
16 defs::{Definition, NameClass, NameRefClass},
17 helpers::pick_best_token,
21 ast::{self, IsString},
22 match_ast, AstNode, AstToken,
24 SyntaxNode, SyntaxToken, TextRange, TextSize, T,
28 doc_links::intra_doc_links::{parse_intra_doc_link, strip_prefixes_suffixes},
29 FilePosition, Semantics,
32 /// Weblink to an item's documentation.
33 pub(crate) type DocumentationLink = String;
35 const MARKDOWN_OPTIONS: Options =
36 Options::ENABLE_FOOTNOTES.union(Options::ENABLE_TABLES).union(Options::ENABLE_TASKLISTS);
38 /// Rewrite documentation links in markdown to point to an online host (e.g. docs.rs)
39 pub(crate) fn rewrite_links(db: &RootDatabase, markdown: &str, definition: Definition) -> String {
40 let mut cb = broken_link_clone_cb;
41 let doc = Parser::new_with_broken_link_callback(markdown, MARKDOWN_OPTIONS, Some(&mut cb));
43 let doc = map_links(doc, |target, title| {
44 // This check is imperfect, there's some overlap between valid intra-doc links
45 // and valid URLs so we choose to be too eager to try to resolve what might be
47 if target.contains("://") {
48 (Some(LinkType::Inline), target.to_string(), title.to_string())
51 // * path-based links: `../../module/struct.MyStruct.html`
52 // * module-based links (AKA intra-doc links): `super::super::module::MyStruct`
53 if let Some((target, title)) = rewrite_intra_doc_link(db, definition, target, title) {
54 return (None, target, title);
56 if let Some(target) = rewrite_url_link(db, definition, target) {
57 return (Some(LinkType::Inline), target, title.to_string());
60 (None, target.to_string(), title.to_string())
63 let mut out = String::new();
64 cmark_resume_with_options(
68 CMarkOptions { code_block_token_count: 3, ..Default::default() },
74 /// Remove all links in markdown documentation.
75 pub(crate) fn remove_links(markdown: &str) -> String {
76 let mut drop_link = false;
78 let mut cb = |_: BrokenLink<'_>| {
79 let empty = InlineStr::try_from("").unwrap();
80 Some((CowStr::Inlined(empty), CowStr::Inlined(empty)))
82 let doc = Parser::new_with_broken_link_callback(markdown, MARKDOWN_OPTIONS, Some(&mut cb));
83 let doc = doc.filter_map(move |evt| match evt {
84 Event::Start(Tag::Link(link_type, target, title)) => {
85 if link_type == LinkType::Inline && target.contains("://") {
86 Some(Event::Start(Tag::Link(link_type, target, title)))
92 Event::End(_) if drop_link => {
99 let mut out = String::new();
100 cmark_resume_with_options(
104 CMarkOptions { code_block_token_count: 3, ..Default::default() },
110 /// Retrieve a link to documentation for the given symbol.
111 pub(crate) fn external_docs(
113 position: &FilePosition,
114 ) -> Option<DocumentationLink> {
115 let sema = &Semantics::new(db);
116 let file = sema.parse(position.file_id).syntax().clone();
117 let token = pick_best_token(file.token_at_offset(position.offset), |kind| match kind {
118 IDENT | INT_NUMBER | T![self] => 3,
119 T!['('] | T![')'] => 2,
120 kind if kind.is_trivia() => 0,
123 let token = sema.descend_into_macros_single(token);
125 let node = token.parent()?;
126 let definition = match_ast! {
128 ast::NameRef(name_ref) => match NameRefClass::classify(sema, &name_ref)? {
129 NameRefClass::Definition(def) => def,
130 NameRefClass::FieldShorthand { local_ref: _, field_ref } => {
131 Definition::Field(field_ref)
134 ast::Name(name) => match NameClass::classify(sema, &name)? {
135 NameClass::Definition(it) | NameClass::ConstReference(it) => it,
136 NameClass::PatFieldShorthand { local_def: _, field_ref } => Definition::Field(field_ref),
142 get_doc_link(db, definition)
145 /// Extracts all links from a given markdown text returning the definition text range, link-text
146 /// and the namespace if known.
147 pub(crate) fn extract_definitions_from_docs(
148 docs: &hir::Documentation,
149 ) -> Vec<(TextRange, String, Option<hir::Namespace>)> {
150 Parser::new_with_broken_link_callback(
153 Some(&mut broken_link_clone_cb),
156 .filter_map(|(event, range)| match event {
157 Event::Start(Tag::Link(_, target, _)) => {
158 let (link, ns) = parse_intra_doc_link(&target);
160 TextRange::new(range.start.try_into().ok()?, range.end.try_into().ok()?),
170 pub(crate) fn resolve_doc_path_for_def(
171 db: &dyn HirDatabase,
174 ns: Option<hir::Namespace>,
175 ) -> Option<Definition> {
177 Definition::Module(it) => it.resolve_doc_path(db, link, ns),
178 Definition::Function(it) => it.resolve_doc_path(db, link, ns),
179 Definition::Adt(it) => it.resolve_doc_path(db, link, ns),
180 Definition::Variant(it) => it.resolve_doc_path(db, link, ns),
181 Definition::Const(it) => it.resolve_doc_path(db, link, ns),
182 Definition::Static(it) => it.resolve_doc_path(db, link, ns),
183 Definition::Trait(it) => it.resolve_doc_path(db, link, ns),
184 Definition::TypeAlias(it) => it.resolve_doc_path(db, link, ns),
185 Definition::Macro(it) => it.resolve_doc_path(db, link, ns),
186 Definition::Field(it) => it.resolve_doc_path(db, link, ns),
187 Definition::SelfType(it) => it.resolve_doc_path(db, link, ns),
188 Definition::BuiltinAttr(_)
189 | Definition::ToolModule(_)
190 | Definition::BuiltinType(_)
191 | Definition::Local(_)
192 | Definition::GenericParam(_)
193 | Definition::Label(_)
194 | Definition::DeriveHelper(_) => None,
196 .map(Definition::from)
199 pub(crate) fn doc_attributes(
200 sema: &Semantics<'_, RootDatabase>,
202 ) -> Option<(hir::AttrsWithOwner, Definition)> {
205 ast::SourceFile(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Module(def))),
206 ast::Module(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Module(def))),
207 ast::Fn(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Function(def))),
208 ast::Struct(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Adt(hir::Adt::Struct(def)))),
209 ast::Union(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Adt(hir::Adt::Union(def)))),
210 ast::Enum(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Adt(hir::Adt::Enum(def)))),
211 ast::Variant(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Variant(def))),
212 ast::Trait(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Trait(def))),
213 ast::Static(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Static(def))),
214 ast::Const(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Const(def))),
215 ast::TypeAlias(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::TypeAlias(def))),
216 ast::Impl(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::SelfType(def))),
217 ast::RecordField(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
218 ast::TupleField(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
219 ast::Macro(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Macro(def))),
220 // ast::Use(it) => sema.to_def(&it).map(|def| (Box::new(it) as _, def.attrs(sema.db))),
226 pub(crate) struct DocCommentToken {
227 doc_token: SyntaxToken,
228 prefix_len: TextSize,
231 pub(crate) fn token_as_doc_comment(doc_token: &SyntaxToken) -> Option<DocCommentToken> {
234 ast::Comment(comment) => TextSize::try_from(comment.prefix().len()).ok(),
235 ast::String(string) => doc_token.parent_ancestors().find_map(ast::Attr::cast)
236 .filter(|attr| attr.simple_name().as_deref() == Some("doc")).and_then(|_| string.open_quote_text_range().map(|it| it.len())),
239 }).map(|prefix_len| DocCommentToken { prefix_len, doc_token: doc_token.clone() })
242 impl DocCommentToken {
243 pub(crate) fn get_definition_with_descend_at<T>(
245 sema: &Semantics<'_, RootDatabase>,
247 // Definition, CommentOwner, range of intra doc link in original file
248 mut cb: impl FnMut(Definition, SyntaxNode, TextRange) -> Option<T>,
250 let DocCommentToken { prefix_len, doc_token } = self;
251 // offset relative to the comments contents
252 let original_start = doc_token.text_range().start();
253 let relative_comment_offset = offset - original_start - prefix_len;
255 sema.descend_into_macros(doc_token).into_iter().find_map(|t| {
256 let (node, descended_prefix_len) = match_ast! {
258 ast::Comment(comment) => (t.parent()?, TextSize::try_from(comment.prefix().len()).ok()?),
259 ast::String(string) => (t.parent_ancestors().skip_while(|n| n.kind() != ATTR).nth(1)?, string.open_quote_text_range()?.len()),
263 let token_start = t.text_range().start();
264 let abs_in_expansion_offset = token_start + relative_comment_offset + descended_prefix_len;
266 let (attributes, def) = doc_attributes(sema, &node)?;
267 let (docs, doc_mapping) = attributes.docs_with_rangemap(sema.db)?;
268 let (in_expansion_range, link, ns) =
269 extract_definitions_from_docs(&docs).into_iter().find_map(|(range, link, ns)| {
270 let mapped = doc_mapping.map(range)?;
271 (mapped.value.contains(abs_in_expansion_offset)).then(|| (mapped.value, link, ns))
273 // get the relative range to the doc/attribute in the expansion
274 let in_expansion_relative_range = in_expansion_range - descended_prefix_len - token_start;
275 // Apply relative range to the original input comment
276 let absolute_range = in_expansion_relative_range + original_start + prefix_len;
277 let def = resolve_doc_path_for_def(sema.db, def, &link, ns)?;
278 cb(def, node, absolute_range)
283 fn broken_link_clone_cb<'a>(link: BrokenLink<'a>) -> Option<(CowStr<'a>, CowStr<'a>)> {
284 Some((/*url*/ link.reference.clone(), /*title*/ link.reference))
288 // BUG: For Option::Some
289 // Returns https://doc.rust-lang.org/nightly/core/prelude/v1/enum.Option.html#variant.Some
290 // Instead of https://doc.rust-lang.org/nightly/core/option/enum.Option.html
292 // This should cease to be a problem if RFC2988 (Stable Rustdoc URLs) is implemented
293 // https://github.com/rust-lang/rfcs/pull/2988
294 fn get_doc_link(db: &RootDatabase, def: Definition) -> Option<String> {
295 let (target, file, frag) = filename_and_frag_for_def(db, def)?;
297 let mut url = get_doc_base_url(db, target)?;
299 if let Some(path) = mod_path_of_def(db, target) {
300 url = url.join(&path).ok()?;
303 url = url.join(&file).ok()?;
304 url.set_fragment(frag.as_deref());
309 fn rewrite_intra_doc_link(
314 ) -> Option<(String, String)> {
315 let (link, ns) = parse_intra_doc_link(target);
317 let resolved = resolve_doc_path_for_def(db, def, link, ns)?;
318 let mut url = get_doc_base_url(db, resolved)?;
320 let (_, file, frag) = filename_and_frag_for_def(db, resolved)?;
321 if let Some(path) = mod_path_of_def(db, resolved) {
322 url = url.join(&path).ok()?;
325 url = url.join(&file).ok()?;
326 url.set_fragment(frag.as_deref());
328 Some((url.into(), strip_prefixes_suffixes(title).to_string()))
331 /// Try to resolve path to local documentation via path-based links (i.e. `../gateway/struct.Shard.html`).
332 fn rewrite_url_link(db: &RootDatabase, def: Definition, target: &str) -> Option<String> {
333 if !(target.contains('#') || target.contains(".html")) {
337 let mut url = get_doc_base_url(db, def)?;
338 let (def, file, frag) = filename_and_frag_for_def(db, def)?;
340 if let Some(path) = mod_path_of_def(db, def) {
341 url = url.join(&path).ok()?;
344 url = url.join(&file).ok()?;
345 url.set_fragment(frag.as_deref());
346 url.join(target).ok().map(Into::into)
349 fn mod_path_of_def(db: &RootDatabase, def: Definition) -> Option<String> {
350 def.canonical_module_path(db).map(|it| {
351 let mut path = String::new();
352 it.flat_map(|it| it.name(db)).for_each(|name| format_to!(path, "{}/", name));
357 /// Rewrites a markdown document, applying 'callback' to each link.
359 events: impl Iterator<Item = Event<'e>>,
360 callback: impl Fn(&str, &str) -> (Option<LinkType>, String, String),
361 ) -> impl Iterator<Item = Event<'e>> {
362 let mut in_link = false;
363 // holds the origin link target on start event and the rewritten one on end event
364 let mut end_link_target: Option<CowStr<'_>> = None;
365 // normally link's type is determined by the type of link tag in the end event,
366 // however in some cases we want to change the link type, for example,
367 // `Shortcut` type parsed from Start/End tags doesn't make sense for url links
368 let mut end_link_type: Option<LinkType> = None;
370 events.map(move |evt| match evt {
371 Event::Start(Tag::Link(link_type, ref target, _)) => {
373 end_link_target = Some(target.clone());
374 end_link_type = Some(link_type);
377 Event::End(Tag::Link(link_type, target, _)) => {
379 Event::End(Tag::Link(
380 end_link_type.unwrap_or(link_type),
381 end_link_target.take().unwrap_or(target),
382 CowStr::Borrowed(""),
385 Event::Text(s) if in_link => {
386 let (link_type, link_target_s, link_name) =
387 callback(&end_link_target.take().unwrap(), &s);
388 end_link_target = Some(CowStr::Boxed(link_target_s.into()));
389 if !matches!(end_link_type, Some(LinkType::Autolink)) {
390 end_link_type = link_type;
392 Event::Text(CowStr::Boxed(link_name.into()))
394 Event::Code(s) if in_link => {
395 let (link_type, link_target_s, link_name) =
396 callback(&end_link_target.take().unwrap(), &s);
397 end_link_target = Some(CowStr::Boxed(link_target_s.into()));
398 if !matches!(end_link_type, Some(LinkType::Autolink)) {
399 end_link_type = link_type;
401 Event::Code(CowStr::Boxed(link_name.into()))
407 /// Get the root URL for the documentation of a definition.
410 /// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
411 /// ^^^^^^^^^^^^^^^^^^^^^^^^^^
413 fn get_doc_base_url(db: &RootDatabase, def: Definition) -> Option<Url> {
414 // special case base url of `BuiltinType` to core
415 // https://github.com/rust-lang/rust-analyzer/issues/12250
416 if let Definition::BuiltinType(..) = def {
417 return Url::parse("https://doc.rust-lang.org/nightly/core/").ok();
420 let krate = def.krate(db)?;
421 let display_name = krate.display_name(db)?;
423 let base = match db.crate_graph()[krate.into()].origin {
424 // std and co do not specify `html_root_url` any longer so we gotta handwrite this ourself.
425 // FIXME: Use the toolchains channel instead of nightly
427 origin @ (LangCrateOrigin::Alloc
428 | LangCrateOrigin::Core
429 | LangCrateOrigin::ProcMacro
430 | LangCrateOrigin::Std
431 | LangCrateOrigin::Test),
433 format!("https://doc.rust-lang.org/nightly/{origin}")
436 krate.get_html_root_url(db).or_else(|| {
437 let version = krate.version(db);
438 // Fallback to docs.rs. This uses `display_name` and can never be
439 // correct, but that's what fallbacks are about.
441 // FIXME: clicking on the link should just open the file in the editor,
442 // instead of falling back to external urls.
444 "https://docs.rs/{krate}/{version}/",
445 krate = display_name,
446 version = version.as_deref().unwrap_or("*")
451 Url::parse(&base).ok()?.join(&format!("{}/", display_name)).ok()
454 /// Get the filename and extension generated for a symbol by rustdoc.
457 /// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
458 /// ^^^^^^^^^^^^^^^^^^^
460 fn filename_and_frag_for_def(
461 db: &dyn HirDatabase,
463 ) -> Option<(Definition, String, Option<String>)> {
464 if let Some(assoc_item) = def.as_assoc_item(db) {
465 let def = match assoc_item.container(db) {
466 AssocItemContainer::Trait(t) => t.into(),
467 AssocItemContainer::Impl(i) => i.self_ty(db).as_adt()?.into(),
469 let (_, file, _) = filename_and_frag_for_def(db, def)?;
470 let frag = get_assoc_item_fragment(db, assoc_item)?;
471 return Some((def, file, Some(frag)));
474 let res = match def {
475 Definition::Adt(adt) => match adt {
476 Adt::Struct(s) => format!("struct.{}.html", s.name(db)),
477 Adt::Enum(e) => format!("enum.{}.html", e.name(db)),
478 Adt::Union(u) => format!("union.{}.html", u.name(db)),
480 Definition::Module(m) => match m.name(db) {
481 // `#[doc(keyword = "...")]` is internal used only by rust compiler
482 Some(name) => match m.attrs(db).by_key("doc").find_string_value_in_tt("keyword") {
484 format!("keyword.{}.html", kw.trim_matches('"'))
486 None => format!("{}/index.html", name),
488 None => String::from("index.html"),
490 Definition::Trait(t) => format!("trait.{}.html", t.name(db)),
491 Definition::TypeAlias(t) => format!("type.{}.html", t.name(db)),
492 Definition::BuiltinType(t) => format!("primitive.{}.html", t.name()),
493 Definition::Function(f) => format!("fn.{}.html", f.name(db)),
494 Definition::Variant(ev) => {
495 format!("enum.{}.html#variant.{}", ev.parent_enum(db).name(db), ev.name(db))
497 Definition::Const(c) => format!("const.{}.html", c.name(db)?),
498 Definition::Static(s) => format!("static.{}.html", s.name(db)),
499 Definition::Macro(mac) => format!("macro.{}.html", mac.name(db)),
500 Definition::Field(field) => {
501 let def = match field.parent_def(db) {
502 hir::VariantDef::Struct(it) => Definition::Adt(it.into()),
503 hir::VariantDef::Union(it) => Definition::Adt(it.into()),
504 hir::VariantDef::Variant(it) => Definition::Variant(it),
506 let (_, file, _) = filename_and_frag_for_def(db, def)?;
507 return Some((def, file, Some(format!("structfield.{}", field.name(db)))));
509 Definition::SelfType(impl_) => {
510 let adt = impl_.self_ty(db).as_adt()?.into();
511 let (_, file, _) = filename_and_frag_for_def(db, adt)?;
512 // FIXME fragment numbering
513 return Some((adt, file, Some(String::from("impl"))));
516 | Definition::GenericParam(_)
517 | Definition::Label(_)
518 | Definition::BuiltinAttr(_)
519 | Definition::ToolModule(_)
520 | Definition::DeriveHelper(_) => return None,
523 Some((def, res, None))
526 /// Get the fragment required to link to a specific field, method, associated type, or associated constant.
529 /// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
532 fn get_assoc_item_fragment(db: &dyn HirDatabase, assoc_item: hir::AssocItem) -> Option<String> {
533 Some(match assoc_item {
534 AssocItem::Function(function) => {
535 let is_trait_method =
536 function.as_assoc_item(db).and_then(|assoc| assoc.containing_trait(db)).is_some();
537 // This distinction may get more complicated when specialization is available.
538 // Rustdoc makes this decision based on whether a method 'has defaultness'.
539 // Currently this is only the case for provided trait methods.
540 if is_trait_method && !function.has_body(db) {
541 format!("tymethod.{}", function.name(db))
543 format!("method.{}", function.name(db))
546 AssocItem::Const(constant) => format!("associatedconstant.{}", constant.name(db)?),
547 AssocItem::TypeAlias(ty) => format!("associatedtype.{}", ty.name(db)),