1 use std::collections::BTreeMap;
5 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
6 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
7 use rustc_middle::middle::privacy::AccessLevels;
8 use rustc_middle::ty::TyCtxt;
9 use rustc_span::symbol::sym;
11 use crate::clean::{self, FakeDefId, GetDefId};
12 use crate::fold::DocFolder;
13 use crate::formats::item_type::ItemType;
14 use crate::formats::Impl;
15 use crate::html::markdown::short_markdown_summary;
16 use crate::html::render::cache::{get_index_search_type, ExternalLocation};
17 use crate::html::render::IndexItem;
19 /// This cache is used to store information about the [`clean::Crate`] being
20 /// rendered in order to provide more useful documentation. This contains
21 /// information like all implementors of a trait, all traits a type implements,
22 /// documentation for all known traits, etc.
24 /// This structure purposefully does not implement `Clone` because it's intended
25 /// to be a fairly large and expensive structure to clone. Instead this adheres
26 /// to `Send` so it may be stored in a `Arc` instance and shared among the various
27 /// rendering threads.
30 /// Maps a type ID to all known implementations for that type. This is only
31 /// recognized for intra-crate `ResolvedPath` types, and is used to print
32 /// out extra documentation on the page of an enum/struct.
34 /// The values of the map are a list of implementations and documentation
35 /// found on that implementation.
36 crate impls: FxHashMap<DefId, Vec<Impl>>,
38 /// Maintains a mapping of local crate `DefId`s to the fully qualified name
39 /// and "short type description" of that node. This is used when generating
40 /// URLs when a type is being linked to. External paths are not located in
41 /// this map because the `External` type itself has all the information
43 crate paths: FxHashMap<DefId, (Vec<String>, ItemType)>,
45 /// Similar to `paths`, but only holds external paths. This is only used for
46 /// generating explicit hyperlinks to other crates.
47 crate external_paths: FxHashMap<DefId, (Vec<String>, ItemType)>,
49 /// Maps local `DefId`s of exported types to fully qualified paths.
50 /// Unlike 'paths', this mapping ignores any renames that occur
51 /// due to 'use' statements.
53 /// This map is used when writing out the special 'implementors'
54 /// javascript file. By using the exact path that the type
55 /// is declared with, we ensure that each path will be identical
56 /// to the path used if the corresponding type is inlined. By
57 /// doing this, we can detect duplicate impls on a trait page, and only display
58 /// the impl for the inlined type.
59 crate exact_paths: FxHashMap<DefId, Vec<String>>,
61 /// This map contains information about all known traits of this crate.
62 /// Implementations of a crate should inherit the documentation of the
63 /// parent trait if no extra documentation is specified, and default methods
64 /// should show up in documentation about trait implementations.
65 crate traits: FxHashMap<DefId, clean::TraitWithExtraInfo>,
67 /// When rendering traits, it's often useful to be able to list all
68 /// implementors of the trait, and this mapping is exactly, that: a mapping
69 /// of trait ids to the list of known implementors of the trait
70 crate implementors: FxHashMap<DefId, Vec<Impl>>,
72 /// Cache of where external crate documentation can be found.
73 crate extern_locations: FxHashMap<CrateNum, ExternalLocation>,
75 /// Cache of where documentation for primitives can be found.
76 crate primitive_locations: FxHashMap<clean::PrimitiveType, DefId>,
78 // Note that external items for which `doc(hidden)` applies to are shown as
79 // non-reachable while local items aren't. This is because we're reusing
80 // the access levels from the privacy check pass.
81 crate access_levels: AccessLevels<DefId>,
83 /// The version of the crate being documented, if given from the `--crate-version` flag.
84 crate crate_version: Option<String>,
86 /// Whether to document private items.
87 /// This is stored in `Cache` so it doesn't need to be passed through all rustdoc functions.
88 crate document_private: bool,
90 /// Crates marked with [`#[doc(masked)]`][doc_masked].
92 /// [doc_masked]: https://doc.rust-lang.org/nightly/unstable-book/language-features/doc-masked.html
93 crate masked_crates: FxHashSet<CrateNum>,
95 // Private fields only used when initially crawling a crate to build a cache
97 parent_stack: Vec<DefId>,
98 parent_is_trait_impl: bool,
101 crate search_index: Vec<IndexItem>,
102 crate deref_trait_did: Option<DefId>,
103 crate deref_mut_trait_did: Option<DefId>,
104 crate owned_box_did: Option<DefId>,
106 // In rare case where a structure is defined in one module but implemented
107 // in another, if the implementing module is parsed before defining module,
108 // then the fully qualified name of the structure isn't presented in `paths`
109 // yet when its implementation methods are being indexed. Caches such methods
110 // and their parent id here and indexes them at the end of crate parsing.
111 crate orphan_impl_items: Vec<(DefId, clean::Item)>,
113 // Similarly to `orphan_impl_items`, sometimes trait impls are picked up
114 // even though the trait itself is not exported. This can happen if a trait
115 // was defined in function/expression scope, since the impl will be picked
116 // up by `collect-trait-impls` but the trait won't be scraped out in the HIR
117 // crawl. In order to prevent crashes when looking for notable traits or
118 // when gathering trait documentation on a type, hold impls here while
119 // folding and add them to the cache later on if we find the trait.
120 orphan_trait_impls: Vec<(DefId, FxHashSet<DefId>, Impl)>,
122 /// All intra-doc links resolved so far.
124 /// Links are indexed by the DefId of the item they document.
125 crate intra_doc_links: BTreeMap<FakeDefId, Vec<clean::ItemLink>>,
128 /// This struct is used to wrap the `cache` and `tcx` in order to run `DocFolder`.
129 struct CacheBuilder<'a, 'tcx> {
130 cache: &'a mut Cache,
136 crate fn new(access_levels: AccessLevels<DefId>, document_private: bool) -> Self {
137 Cache { access_levels, document_private, ..Cache::default() }
140 /// Populates the `Cache` with more data. The returned `Crate` will be missing some data that was
141 /// in `krate` due to the data being moved into the `Cache`.
144 mut krate: clean::Crate,
146 extern_html_root_urls: &BTreeMap<String, String>,
149 // Crawl the crate to build various caches used for the output
150 debug!(?self.crate_version);
151 self.traits = krate.external_traits.take();
153 // Cache where all our extern crates are located
154 // FIXME: this part is specific to HTML so it'd be nice to remove it from the common code
155 for &(n, ref e) in &krate.externs {
156 let name = e.name(tcx);
157 let extern_url = extern_html_root_urls.get(&*name.as_str()).map(|u| &**u);
158 let did = DefId { krate: n, index: CRATE_DEF_INDEX };
159 self.extern_locations.insert(n, e.location(extern_url, &dst, tcx));
160 self.external_paths.insert(did, (vec![name.to_string()], ItemType::Module));
163 // Cache where all known primitives have their documentation located.
165 // Favor linking to as local extern as possible, so iterate all crates in
166 // reverse topological order.
167 for &(_, ref e) in krate.externs.iter().rev() {
168 for &(def_id, prim) in &e.primitives(tcx) {
169 self.primitive_locations.insert(prim, def_id);
172 for &(def_id, prim) in &krate.primitives {
173 self.primitive_locations.insert(prim, def_id);
176 krate = CacheBuilder { tcx, cache: self, empty_cache: Cache::default() }.fold_crate(krate);
178 for (trait_did, dids, impl_) in self.orphan_trait_impls.drain(..) {
179 if self.traits.contains_key(&trait_did) {
181 self.impls.entry(did).or_default().push(impl_.clone());
190 impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
191 fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> {
192 if item.def_id.is_local() {
193 debug!("folding {} \"{:?}\", id {:?}", item.type_(), item.name, item.def_id);
196 // If this is a stripped module,
197 // we don't want it or its children in the search index.
198 let orig_stripped_mod = match *item.kind {
199 clean::StrippedItem(box clean::ModuleItem(..)) => {
200 mem::replace(&mut self.cache.stripped_mod, true)
202 _ => self.cache.stripped_mod,
205 // If the impl is from a masked crate or references something from a
206 // masked crate then remove it completely.
207 if let clean::ImplItem(ref i) = *item.kind {
208 if self.cache.masked_crates.contains(&item.def_id.krate())
209 || i.trait_.def_id().map_or(false, |d| self.cache.masked_crates.contains(&d.krate))
210 || i.for_.def_id().map_or(false, |d| self.cache.masked_crates.contains(&d.krate))
216 // Propagate a trait method's documentation to all implementors of the
218 if let clean::TraitItem(ref t) = *item.kind {
219 self.cache.traits.entry(item.def_id.expect_real()).or_insert_with(|| {
220 clean::TraitWithExtraInfo {
222 is_notable: item.attrs.has_doc_flag(sym::notable_trait),
227 // Collect all the implementors of traits.
228 if let clean::ImplItem(ref i) = *item.kind {
229 if let Some(did) = i.trait_.def_id() {
230 if i.blanket_impl.is_none() {
235 .push(Impl { impl_item: item.clone() });
240 // Index this method for searching later on.
241 if let Some(ref s) = item.name {
242 let (parent, is_inherent_impl_item) = match *item.kind {
243 clean::StrippedItem(..) => ((None, None), false),
244 clean::AssocConstItem(..) | clean::TypedefItem(_, true)
245 if self.cache.parent_is_trait_impl =>
247 // skip associated items in trait impls
248 ((None, None), false)
250 clean::AssocTypeItem(..)
251 | clean::TyMethodItem(..)
252 | clean::StructFieldItem(..)
253 | clean::VariantItem(..) => (
255 Some(*self.cache.parent_stack.last().expect("parent_stack is empty")),
256 Some(&self.cache.stack[..self.cache.stack.len() - 1]),
260 clean::MethodItem(..) | clean::AssocConstItem(..) => {
261 if self.cache.parent_stack.is_empty() {
262 ((None, None), false)
264 let last = self.cache.parent_stack.last().expect("parent_stack is empty 2");
266 let path = match self.cache.paths.get(&did) {
267 // The current stack not necessarily has correlation
268 // for where the type was defined. On the other
269 // hand, `paths` always has the right
270 // information if present.
277 )) => Some(&fqp[..fqp.len() - 1]),
278 Some(..) => Some(&*self.cache.stack),
281 ((Some(*last), path), true)
284 _ => ((None, Some(&*self.cache.stack)), false),
288 (parent, Some(path)) if is_inherent_impl_item || !self.cache.stripped_mod => {
289 debug_assert!(!item.is_stripped());
291 // A crate has a module at its root, containing all items,
292 // which should not be indexed. The crate-item itself is
293 // inserted later on when serializing the search-index.
294 if item.def_id.index().map_or(false, |idx| idx != CRATE_DEF_INDEX) {
295 self.cache.search_index.push(IndexItem {
298 path: path.join("::"),
301 .map_or_else(String::new, |x| short_markdown_summary(&x.as_str())),
304 search_type: get_index_search_type(&item, &self.empty_cache, self.tcx),
305 aliases: item.attrs.get_doc_aliases(),
309 (Some(parent), None) if is_inherent_impl_item => {
310 // We have a parent, but we don't know where they're
311 // defined yet. Wait for later to index this item.
312 self.cache.orphan_impl_items.push((parent, item.clone()));
318 // Keep track of the fully qualified path for this item.
319 let pushed = match item.name {
320 Some(n) if !n.is_empty() => {
321 self.cache.stack.push(n.to_string());
328 clean::StructItem(..)
329 | clean::EnumItem(..)
330 | clean::TypedefItem(..)
331 | clean::TraitItem(..)
332 | clean::TraitAliasItem(..)
333 | clean::FunctionItem(..)
334 | clean::ModuleItem(..)
335 | clean::ForeignFunctionItem(..)
336 | clean::ForeignStaticItem(..)
337 | clean::ConstantItem(..)
338 | clean::StaticItem(..)
339 | clean::UnionItem(..)
340 | clean::ForeignTypeItem
341 | clean::MacroItem(..)
342 | clean::ProcMacroItem(..)
343 | clean::VariantItem(..) => {
344 if !self.cache.stripped_mod {
345 // Re-exported items mean that the same id can show up twice
346 // in the rustdoc ast that we're looking at. We know,
347 // however, that a re-exported item doesn't show up in the
348 // `public_items` map, so we can skip inserting into the
349 // paths map if there was already an entry present and we're
350 // not a public item.
351 if !self.cache.paths.contains_key(&item.def_id.expect_real())
352 || self.cache.access_levels.is_public(item.def_id.expect_real())
354 self.cache.paths.insert(
355 item.def_id.expect_real(),
356 (self.cache.stack.clone(), item.type_()),
361 clean::PrimitiveItem(..) => {
364 .insert(item.def_id.expect_real(), (self.cache.stack.clone(), item.type_()));
367 clean::ExternCrateItem { .. }
368 | clean::ImportItem(..)
369 | clean::OpaqueTyItem(..)
370 | clean::ImplItem(..)
371 | clean::TyMethodItem(..)
372 | clean::MethodItem(..)
373 | clean::StructFieldItem(..)
374 | clean::AssocConstItem(..)
375 | clean::AssocTypeItem(..)
376 | clean::StrippedItem(..)
377 | clean::KeywordItem(..) => {
378 // FIXME: Do these need handling?
379 // The person writing this comment doesn't know.
380 // So would rather leave them to an expert,
381 // as at least the list is better than `_ => {}`.
385 // Maintain the parent stack
386 let orig_parent_is_trait_impl = self.cache.parent_is_trait_impl;
387 let parent_pushed = match *item.kind {
389 | clean::EnumItem(..)
390 | clean::ForeignTypeItem
391 | clean::StructItem(..)
392 | clean::UnionItem(..)
393 | clean::VariantItem(..) => {
394 self.cache.parent_stack.push(item.def_id.expect_real());
395 self.cache.parent_is_trait_impl = false;
398 clean::ImplItem(ref i) => {
399 self.cache.parent_is_trait_impl = i.trait_.is_some();
401 clean::ResolvedPath { did, .. } => {
402 self.cache.parent_stack.push(did);
408 .and_then(|t| self.cache.primitive_locations.get(&t).cloned());
411 self.cache.parent_stack.push(did);
422 // Once we've recursively found all the generics, hoard off all the
423 // implementations elsewhere.
424 let item = self.fold_item_recur(item);
425 let ret = if let clean::Item { kind: box clean::ImplItem(ref i), .. } = item {
426 // Figure out the id of this impl. This may map to a
427 // primitive rather than always to a struct/enum.
428 // Note: matching twice to restrict the lifetime of the `i` borrow.
429 let mut dids = FxHashSet::default();
431 clean::ResolvedPath { did, .. }
432 | clean::BorrowedRef { type_: box clean::ResolvedPath { did, .. }, .. } => {
438 .and_then(|t| self.cache.primitive_locations.get(&t).cloned());
440 if let Some(did) = did {
446 if let Some(generics) = i.trait_.as_ref().and_then(|t| t.generics()) {
447 for bound in generics {
448 if let Some(did) = bound.def_id() {
453 let impl_item = Impl { impl_item: item };
454 if impl_item.trait_did().map_or(true, |d| self.cache.traits.contains_key(&d)) {
456 self.cache.impls.entry(did).or_insert(vec![]).push(impl_item.clone());
459 let trait_did = impl_item.trait_did().expect("no trait did");
460 self.cache.orphan_trait_impls.push((trait_did, dids, impl_item));
468 self.cache.stack.pop().expect("stack already empty");
471 self.cache.parent_stack.pop().expect("parent stack already empty");
473 self.cache.stripped_mod = orig_stripped_mod;
474 self.cache.parent_is_trait_impl = orig_parent_is_trait_impl;