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, Crate, HasAttrs};
15 defs::{Definition, NameClass, NameRefClass},
16 helpers::pick_best_token,
20 ast::{self, IsString},
21 match_ast, AstNode, AstToken,
23 SyntaxNode, SyntaxToken, TextRange, TextSize, T,
27 doc_links::intra_doc_links::{parse_intra_doc_link, strip_prefixes_suffixes},
28 FilePosition, Semantics,
31 /// Weblink to an item's documentation.
32 pub(crate) type DocumentationLink = String;
34 const MARKDOWN_OPTIONS: Options =
35 Options::ENABLE_FOOTNOTES.union(Options::ENABLE_TABLES).union(Options::ENABLE_TASKLISTS);
37 /// Rewrite documentation links in markdown to point to an online host (e.g. docs.rs)
38 pub(crate) fn rewrite_links(db: &RootDatabase, markdown: &str, definition: Definition) -> String {
39 let mut cb = broken_link_clone_cb;
40 let doc = Parser::new_with_broken_link_callback(markdown, MARKDOWN_OPTIONS, Some(&mut cb));
42 let doc = map_links(doc, |target, title| {
43 // This check is imperfect, there's some overlap between valid intra-doc links
44 // and valid URLs so we choose to be too eager to try to resolve what might be
46 if target.contains("://") {
47 (target.to_string(), title.to_string())
50 // * path-based links: `../../module/struct.MyStruct.html`
51 // * module-based links (AKA intra-doc links): `super::super::module::MyStruct`
52 if let Some(rewritten) = rewrite_intra_doc_link(db, definition, target, title) {
55 if let Some(target) = rewrite_url_link(db, definition, target) {
56 return (target, title.to_string());
59 (target.to_string(), title.to_string())
62 let mut out = String::new();
63 cmark_resume_with_options(
67 CMarkOptions { code_block_token_count: 3, ..Default::default() },
73 /// Remove all links in markdown documentation.
74 pub(crate) fn remove_links(markdown: &str) -> String {
75 let mut drop_link = false;
77 let mut cb = |_: BrokenLink| {
78 let empty = InlineStr::try_from("").unwrap();
79 Some((CowStr::Inlined(empty), CowStr::Inlined(empty)))
81 let doc = Parser::new_with_broken_link_callback(markdown, MARKDOWN_OPTIONS, Some(&mut cb));
82 let doc = doc.filter_map(move |evt| match evt {
83 Event::Start(Tag::Link(link_type, target, title)) => {
84 if link_type == LinkType::Inline && target.contains("://") {
85 Some(Event::Start(Tag::Link(link_type, target, title)))
91 Event::End(_) if drop_link => {
98 let mut out = String::new();
99 cmark_resume_with_options(
103 CMarkOptions { code_block_token_count: 3, ..Default::default() },
109 /// Retrieve a link to documentation for the given symbol.
110 pub(crate) fn external_docs(
112 position: &FilePosition,
113 ) -> Option<DocumentationLink> {
114 let sema = &Semantics::new(db);
115 let file = sema.parse(position.file_id).syntax().clone();
116 let token = pick_best_token(file.token_at_offset(position.offset), |kind| match kind {
117 IDENT | INT_NUMBER | T![self] => 3,
118 T!['('] | T![')'] => 2,
119 kind if kind.is_trivia() => 0,
122 let token = sema.descend_into_macros_single(token);
124 let node = token.parent()?;
125 let definition = match_ast! {
127 ast::NameRef(name_ref) => match NameRefClass::classify(sema, &name_ref)? {
128 NameRefClass::Definition(def) => def,
129 NameRefClass::FieldShorthand { local_ref: _, field_ref } => {
130 Definition::Field(field_ref)
133 ast::Name(name) => match NameClass::classify(sema, &name)? {
134 NameClass::Definition(it) | NameClass::ConstReference(it) => it,
135 NameClass::PatFieldShorthand { local_def: _, field_ref } => Definition::Field(field_ref),
141 get_doc_link(db, definition)
144 /// Extracts all links from a given markdown text returning the definition text range, link-text
145 /// and the namespace if known.
146 pub(crate) fn extract_definitions_from_docs(
147 docs: &hir::Documentation,
148 ) -> Vec<(TextRange, String, Option<hir::Namespace>)> {
149 Parser::new_with_broken_link_callback(
152 Some(&mut broken_link_clone_cb),
155 .filter_map(|(event, range)| match event {
156 Event::Start(Tag::Link(_, target, _)) => {
157 let (link, ns) = parse_intra_doc_link(&target);
159 TextRange::new(range.start.try_into().ok()?, range.end.try_into().ok()?),
169 pub(crate) fn resolve_doc_path_for_def(
170 db: &dyn HirDatabase,
173 ns: Option<hir::Namespace>,
174 ) -> Option<Definition> {
176 Definition::Module(it) => it.resolve_doc_path(db, link, ns),
177 Definition::Function(it) => it.resolve_doc_path(db, link, ns),
178 Definition::Adt(it) => it.resolve_doc_path(db, link, ns),
179 Definition::Variant(it) => it.resolve_doc_path(db, link, ns),
180 Definition::Const(it) => it.resolve_doc_path(db, link, ns),
181 Definition::Static(it) => it.resolve_doc_path(db, link, ns),
182 Definition::Trait(it) => it.resolve_doc_path(db, link, ns),
183 Definition::TypeAlias(it) => it.resolve_doc_path(db, link, ns),
184 Definition::Macro(it) => it.resolve_doc_path(db, link, ns),
185 Definition::Field(it) => it.resolve_doc_path(db, link, ns),
186 Definition::BuiltinAttr(_)
187 | Definition::ToolModule(_)
188 | Definition::BuiltinType(_)
189 | Definition::SelfType(_)
190 | Definition::Local(_)
191 | Definition::GenericParam(_)
192 | Definition::Label(_) => None,
194 .map(Definition::from)
197 pub(crate) fn doc_attributes(
198 sema: &Semantics<RootDatabase>,
200 ) -> Option<(hir::AttrsWithOwner, Definition)> {
203 ast::SourceFile(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Module(def))),
204 ast::Module(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Module(def))),
205 ast::Fn(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Function(def))),
206 ast::Struct(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Adt(hir::Adt::Struct(def)))),
207 ast::Union(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Adt(hir::Adt::Union(def)))),
208 ast::Enum(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Adt(hir::Adt::Enum(def)))),
209 ast::Variant(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Variant(def))),
210 ast::Trait(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Trait(def))),
211 ast::Static(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Static(def))),
212 ast::Const(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Const(def))),
213 ast::TypeAlias(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::TypeAlias(def))),
214 ast::Impl(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::SelfType(def))),
215 ast::RecordField(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
216 ast::TupleField(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
217 ast::Macro(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Macro(def))),
218 // ast::Use(it) => sema.to_def(&it).map(|def| (Box::new(it) as _, def.attrs(sema.db))),
224 pub(crate) struct DocCommentToken {
225 doc_token: SyntaxToken,
226 prefix_len: TextSize,
229 pub(crate) fn token_as_doc_comment(doc_token: &SyntaxToken) -> Option<DocCommentToken> {
232 ast::Comment(comment) => TextSize::try_from(comment.prefix().len()).ok(),
233 ast::String(string) => doc_token.ancestors().find_map(ast::Attr::cast)
234 .filter(|attr| attr.simple_name().as_deref() == Some("doc")).and_then(|_| string.open_quote_text_range().map(|it| it.len())),
237 }).map(|prefix_len| DocCommentToken { prefix_len, doc_token: doc_token.clone() })
240 impl DocCommentToken {
241 pub(crate) fn get_definition_with_descend_at<T>(
243 sema: &Semantics<RootDatabase>,
245 // Definition, CommentOwner, range of intra doc link in original file
246 mut cb: impl FnMut(Definition, SyntaxNode, TextRange) -> Option<T>,
248 let DocCommentToken { prefix_len, doc_token } = self;
249 // offset relative to the comments contents
250 let original_start = doc_token.text_range().start();
251 let relative_comment_offset = offset - original_start - prefix_len;
253 sema.descend_into_macros(doc_token).into_iter().find_map(|t| {
254 let (node, descended_prefix_len) = match_ast! {
256 ast::Comment(comment) => (t.parent()?, TextSize::try_from(comment.prefix().len()).ok()?),
257 ast::String(string) => (t.ancestors().skip_while(|n| n.kind() != ATTR).nth(1)?, string.open_quote_text_range()?.len()),
261 let token_start = t.text_range().start();
262 let abs_in_expansion_offset = token_start + relative_comment_offset + descended_prefix_len;
264 let (attributes, def) = doc_attributes(sema, &node)?;
265 let (docs, doc_mapping) = attributes.docs_with_rangemap(sema.db)?;
266 let (in_expansion_range, link, ns) =
267 extract_definitions_from_docs(&docs).into_iter().find_map(|(range, link, ns)| {
268 let mapped = doc_mapping.map(range)?;
269 (mapped.value.contains(abs_in_expansion_offset)).then(|| (mapped.value, link, ns))
271 // get the relative range to the doc/attribute in the expansion
272 let in_expansion_relative_range = in_expansion_range - descended_prefix_len - token_start;
273 // Apply relative range to the original input comment
274 let absolute_range = in_expansion_relative_range + original_start + prefix_len;
275 let def = resolve_doc_path_for_def(sema.db, def, &link, ns)?;
276 cb(def, node, absolute_range)
281 fn broken_link_clone_cb<'a>(link: BrokenLink<'a>) -> Option<(CowStr<'a>, CowStr<'a>)> {
282 Some((/*url*/ link.reference.clone(), /*title*/ link.reference))
286 // BUG: For Option::Some
287 // Returns https://doc.rust-lang.org/nightly/core/prelude/v1/enum.Option.html#variant.Some
288 // Instead of https://doc.rust-lang.org/nightly/core/option/enum.Option.html
290 // This should cease to be a problem if RFC2988 (Stable Rustdoc URLs) is implemented
291 // https://github.com/rust-lang/rfcs/pull/2988
292 fn get_doc_link(db: &RootDatabase, def: Definition) -> Option<String> {
293 let (target, file, frag) = filename_and_frag_for_def(db, def)?;
295 let krate = crate_of_def(db, target)?;
296 let mut url = get_doc_base_url(db, &krate)?;
298 if let Some(path) = mod_path_of_def(db, target) {
299 url = url.join(&path).ok()?;
302 url = url.join(&file).ok()?;
303 url.set_fragment(frag.as_deref());
308 fn rewrite_intra_doc_link(
313 ) -> Option<(String, String)> {
314 let (link, ns) = parse_intra_doc_link(target);
316 let resolved = resolve_doc_path_for_def(db, def, link, ns)?;
317 let krate = crate_of_def(db, resolved)?;
318 let mut url = get_doc_base_url(db, &krate)?;
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 krate = crate_of_def(db, def)?;
338 let mut url = get_doc_base_url(db, &krate)?;
339 let (def, file, frag) = filename_and_frag_for_def(db, def)?;
341 if let Some(path) = mod_path_of_def(db, def) {
342 url = url.join(&path).ok()?;
345 url = url.join(&file).ok()?;
346 url.set_fragment(frag.as_deref());
347 url.join(target).ok().map(Into::into)
350 fn crate_of_def(db: &RootDatabase, def: Definition) -> Option<Crate> {
351 let krate = match def {
352 // Definition::module gives back the parent module, we don't want that as it fails for root modules
353 Definition::Module(module) => module.krate(),
354 def => def.module(db)?.krate(),
359 fn mod_path_of_def(db: &RootDatabase, def: Definition) -> Option<String> {
360 def.canonical_module_path(db).map(|it| {
361 let mut path = String::new();
362 it.flat_map(|it| it.name(db)).for_each(|name| format_to!(path, "{}/", name));
367 /// Rewrites a markdown document, applying 'callback' to each link.
369 events: impl Iterator<Item = Event<'e>>,
370 callback: impl Fn(&str, &str) -> (String, String),
371 ) -> impl Iterator<Item = Event<'e>> {
372 let mut in_link = false;
373 let mut link_target: Option<CowStr> = None;
375 events.map(move |evt| match evt {
376 Event::Start(Tag::Link(_, ref target, _)) => {
378 link_target = Some(target.clone());
381 Event::End(Tag::Link(link_type, target, _)) => {
383 Event::End(Tag::Link(
385 link_target.take().unwrap_or(target),
386 CowStr::Borrowed(""),
389 Event::Text(s) if in_link => {
390 let (link_target_s, link_name) = callback(&link_target.take().unwrap(), &s);
391 link_target = Some(CowStr::Boxed(link_target_s.into()));
392 Event::Text(CowStr::Boxed(link_name.into()))
394 Event::Code(s) if in_link => {
395 let (link_target_s, link_name) = callback(&link_target.take().unwrap(), &s);
396 link_target = Some(CowStr::Boxed(link_target_s.into()));
397 Event::Code(CowStr::Boxed(link_name.into()))
403 /// Get the root URL for the documentation of a crate.
406 /// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
407 /// ^^^^^^^^^^^^^^^^^^^^^^^^^^
409 fn get_doc_base_url(db: &RootDatabase, krate: &Crate) -> Option<Url> {
410 let display_name = krate.display_name(db)?;
411 let base = match &**display_name.crate_name() {
412 // std and co do not specify `html_root_url` any longer so we gotta handwrite this ourself.
413 // FIXME: Use the toolchains channel instead of nightly
414 name @ ("core" | "std" | "alloc" | "proc_macro" | "test") => {
415 format!("https://doc.rust-lang.org/nightly/{}", name)
418 krate.get_html_root_url(db).or_else(|| {
419 let version = krate.version(db);
420 // Fallback to docs.rs. This uses `display_name` and can never be
421 // correct, but that's what fallbacks are about.
423 // FIXME: clicking on the link should just open the file in the editor,
424 // instead of falling back to external urls.
426 "https://docs.rs/{krate}/{version}/",
427 krate = display_name,
428 version = version.as_deref().unwrap_or("*")
433 Url::parse(&base).ok()?.join(&format!("{}/", display_name)).ok()
436 /// Get the filename and extension generated for a symbol by rustdoc.
439 /// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
440 /// ^^^^^^^^^^^^^^^^^^^
442 fn filename_and_frag_for_def(
443 db: &dyn HirDatabase,
445 ) -> Option<(Definition, String, Option<String>)> {
446 if let Some(assoc_item) = def.as_assoc_item(db) {
447 let def = match assoc_item.container(db) {
448 AssocItemContainer::Trait(t) => t.into(),
449 AssocItemContainer::Impl(i) => i.self_ty(db).as_adt()?.into(),
451 let (_, file, _) = filename_and_frag_for_def(db, def)?;
452 let frag = get_assoc_item_fragment(db, assoc_item)?;
453 return Some((def, file, Some(frag)));
456 let res = match def {
457 Definition::Adt(adt) => match adt {
458 Adt::Struct(s) => format!("struct.{}.html", s.name(db)),
459 Adt::Enum(e) => format!("enum.{}.html", e.name(db)),
460 Adt::Union(u) => format!("union.{}.html", u.name(db)),
462 Definition::Module(m) => match m.name(db) {
463 Some(name) => format!("{}/index.html", name),
464 None => String::from("index.html"),
466 Definition::Trait(t) => format!("trait.{}.html", t.name(db)),
467 Definition::TypeAlias(t) => format!("type.{}.html", t.name(db)),
468 Definition::BuiltinType(t) => format!("primitive.{}.html", t.name()),
469 Definition::Function(f) => format!("fn.{}.html", f.name(db)),
470 Definition::Variant(ev) => {
471 format!("enum.{}.html#variant.{}", ev.parent_enum(db).name(db), ev.name(db))
473 Definition::Const(c) => format!("const.{}.html", c.name(db)?),
474 Definition::Static(s) => format!("static.{}.html", s.name(db)),
475 Definition::Macro(mac) => format!("macro.{}.html", mac.name(db)),
476 Definition::Field(field) => {
477 let def = match field.parent_def(db) {
478 hir::VariantDef::Struct(it) => Definition::Adt(it.into()),
479 hir::VariantDef::Union(it) => Definition::Adt(it.into()),
480 hir::VariantDef::Variant(it) => Definition::Variant(it),
482 let (_, file, _) = filename_and_frag_for_def(db, def)?;
483 return Some((def, file, Some(format!("structfield.{}", field.name(db)))));
485 Definition::SelfType(impl_) => {
486 let adt = impl_.self_ty(db).as_adt()?.into();
487 let (_, file, _) = filename_and_frag_for_def(db, adt)?;
488 // FIXME fragment numbering
489 return Some((adt, file, Some(String::from("impl"))));
492 | Definition::GenericParam(_)
493 | Definition::Label(_)
494 | Definition::BuiltinAttr(_)
495 | Definition::ToolModule(_) => return None,
498 Some((def, res, None))
501 /// Get the fragment required to link to a specific field, method, associated type, or associated constant.
504 /// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
507 fn get_assoc_item_fragment(db: &dyn HirDatabase, assoc_item: hir::AssocItem) -> Option<String> {
508 Some(match assoc_item {
509 AssocItem::Function(function) => {
510 let is_trait_method =
511 function.as_assoc_item(db).and_then(|assoc| assoc.containing_trait(db)).is_some();
512 // This distinction may get more complicated when specialization is available.
513 // Rustdoc makes this decision based on whether a method 'has defaultness'.
514 // Currently this is only the case for provided trait methods.
515 if is_trait_method && !function.has_body(db) {
516 format!("tymethod.{}", function.name(db))
518 format!("method.{}", function.name(db))
521 AssocItem::Const(constant) => format!("associatedconstant.{}", constant.name(db)?),
522 AssocItem::TypeAlias(ty) => format!("associatedtype.{}", ty.name(db)),