diff options
Diffstat (limited to 'src/librustdoc/formats/cache.rs')
-rw-r--r-- | src/librustdoc/formats/cache.rs | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/src/librustdoc/formats/cache.rs b/src/librustdoc/formats/cache.rs new file mode 100644 index 000000000..2b2691e53 --- /dev/null +++ b/src/librustdoc/formats/cache.rs @@ -0,0 +1,569 @@ +use std::mem; + +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_hir::def_id::{CrateNum, DefId}; +use rustc_middle::middle::privacy::AccessLevels; +use rustc_middle::ty::{self, TyCtxt}; +use rustc_span::{sym, Symbol}; + +use crate::clean::{self, types::ExternalLocation, ExternalCrate, ItemId, PrimitiveType}; +use crate::core::DocContext; +use crate::fold::DocFolder; +use crate::formats::item_type::ItemType; +use crate::formats::Impl; +use crate::html::format::join_with_double_colon; +use crate::html::markdown::short_markdown_summary; +use crate::html::render::search_index::get_function_type_for_search; +use crate::html::render::IndexItem; + +/// This cache is used to store information about the [`clean::Crate`] being +/// rendered in order to provide more useful documentation. This contains +/// information like all implementors of a trait, all traits a type implements, +/// documentation for all known traits, etc. +/// +/// This structure purposefully does not implement `Clone` because it's intended +/// to be a fairly large and expensive structure to clone. Instead this adheres +/// to `Send` so it may be stored in an `Arc` instance and shared among the various +/// rendering threads. +#[derive(Default)] +pub(crate) struct Cache { + /// Maps a type ID to all known implementations for that type. This is only + /// recognized for intra-crate [`clean::Type::Path`]s, and is used to print + /// out extra documentation on the page of an enum/struct. + /// + /// The values of the map are a list of implementations and documentation + /// found on that implementation. + pub(crate) impls: FxHashMap<DefId, Vec<Impl>>, + + /// Maintains a mapping of local crate `DefId`s to the fully qualified name + /// and "short type description" of that node. This is used when generating + /// URLs when a type is being linked to. External paths are not located in + /// this map because the `External` type itself has all the information + /// necessary. + pub(crate) paths: FxHashMap<DefId, (Vec<Symbol>, ItemType)>, + + /// Similar to `paths`, but only holds external paths. This is only used for + /// generating explicit hyperlinks to other crates. + pub(crate) external_paths: FxHashMap<DefId, (Vec<Symbol>, ItemType)>, + + /// Maps local `DefId`s of exported types to fully qualified paths. + /// Unlike 'paths', this mapping ignores any renames that occur + /// due to 'use' statements. + /// + /// This map is used when writing out the special 'implementors' + /// javascript file. By using the exact path that the type + /// is declared with, we ensure that each path will be identical + /// to the path used if the corresponding type is inlined. By + /// doing this, we can detect duplicate impls on a trait page, and only display + /// the impl for the inlined type. + pub(crate) exact_paths: FxHashMap<DefId, Vec<Symbol>>, + + /// This map contains information about all known traits of this crate. + /// Implementations of a crate should inherit the documentation of the + /// parent trait if no extra documentation is specified, and default methods + /// should show up in documentation about trait implementations. + pub(crate) traits: FxHashMap<DefId, clean::TraitWithExtraInfo>, + + /// When rendering traits, it's often useful to be able to list all + /// implementors of the trait, and this mapping is exactly, that: a mapping + /// of trait ids to the list of known implementors of the trait + pub(crate) implementors: FxHashMap<DefId, Vec<Impl>>, + + /// Cache of where external crate documentation can be found. + pub(crate) extern_locations: FxHashMap<CrateNum, ExternalLocation>, + + /// Cache of where documentation for primitives can be found. + pub(crate) primitive_locations: FxHashMap<clean::PrimitiveType, DefId>, + + // Note that external items for which `doc(hidden)` applies to are shown as + // non-reachable while local items aren't. This is because we're reusing + // the access levels from the privacy check pass. + pub(crate) access_levels: AccessLevels<DefId>, + + /// The version of the crate being documented, if given from the `--crate-version` flag. + pub(crate) crate_version: Option<String>, + + /// Whether to document private items. + /// This is stored in `Cache` so it doesn't need to be passed through all rustdoc functions. + pub(crate) document_private: bool, + + /// Crates marked with [`#[doc(masked)]`][doc_masked]. + /// + /// [doc_masked]: https://doc.rust-lang.org/nightly/unstable-book/language-features/doc-masked.html + pub(crate) masked_crates: FxHashSet<CrateNum>, + + // Private fields only used when initially crawling a crate to build a cache + stack: Vec<Symbol>, + parent_stack: Vec<ParentStackItem>, + stripped_mod: bool, + + pub(crate) search_index: Vec<IndexItem>, + + // In rare case where a structure is defined in one module but implemented + // in another, if the implementing module is parsed before defining module, + // then the fully qualified name of the structure isn't presented in `paths` + // yet when its implementation methods are being indexed. Caches such methods + // and their parent id here and indexes them at the end of crate parsing. + pub(crate) orphan_impl_items: Vec<OrphanImplItem>, + + // Similarly to `orphan_impl_items`, sometimes trait impls are picked up + // even though the trait itself is not exported. This can happen if a trait + // was defined in function/expression scope, since the impl will be picked + // up by `collect-trait-impls` but the trait won't be scraped out in the HIR + // crawl. In order to prevent crashes when looking for notable traits or + // when gathering trait documentation on a type, hold impls here while + // folding and add them to the cache later on if we find the trait. + orphan_trait_impls: Vec<(DefId, FxHashSet<DefId>, Impl)>, + + /// All intra-doc links resolved so far. + /// + /// Links are indexed by the DefId of the item they document. + pub(crate) intra_doc_links: FxHashMap<ItemId, Vec<clean::ItemLink>>, + /// Cfg that have been hidden via #![doc(cfg_hide(...))] + pub(crate) hidden_cfg: FxHashSet<clean::cfg::Cfg>, +} + +/// This struct is used to wrap the `cache` and `tcx` in order to run `DocFolder`. +struct CacheBuilder<'a, 'tcx> { + cache: &'a mut Cache, + /// This field is used to prevent duplicated impl blocks. + impl_ids: FxHashMap<DefId, FxHashSet<DefId>>, + tcx: TyCtxt<'tcx>, +} + +impl Cache { + pub(crate) fn new(access_levels: AccessLevels<DefId>, document_private: bool) -> Self { + Cache { access_levels, document_private, ..Cache::default() } + } + + /// Populates the `Cache` with more data. The returned `Crate` will be missing some data that was + /// in `krate` due to the data being moved into the `Cache`. + pub(crate) fn populate(cx: &mut DocContext<'_>, mut krate: clean::Crate) -> clean::Crate { + let tcx = cx.tcx; + + // Crawl the crate to build various caches used for the output + debug!(?cx.cache.crate_version); + cx.cache.traits = krate.external_traits.take(); + + // Cache where all our extern crates are located + // FIXME: this part is specific to HTML so it'd be nice to remove it from the common code + for &crate_num in cx.tcx.crates(()) { + let e = ExternalCrate { crate_num }; + + let name = e.name(tcx); + let render_options = &cx.render_options; + let extern_url = render_options.extern_html_root_urls.get(name.as_str()).map(|u| &**u); + let extern_url_takes_precedence = render_options.extern_html_root_takes_precedence; + let dst = &render_options.output; + let location = e.location(extern_url, extern_url_takes_precedence, dst, tcx); + cx.cache.extern_locations.insert(e.crate_num, location); + cx.cache.external_paths.insert(e.def_id(), (vec![name], ItemType::Module)); + } + + // FIXME: avoid this clone (requires implementing Default manually) + cx.cache.primitive_locations = PrimitiveType::primitive_locations(tcx).clone(); + for (prim, &def_id) in &cx.cache.primitive_locations { + let crate_name = tcx.crate_name(def_id.krate); + // Recall that we only allow primitive modules to be at the root-level of the crate. + // If that restriction is ever lifted, this will have to include the relative paths instead. + cx.cache + .external_paths + .insert(def_id, (vec![crate_name, prim.as_sym()], ItemType::Primitive)); + } + + let (krate, mut impl_ids) = { + let mut cache_builder = + CacheBuilder { tcx, cache: &mut cx.cache, impl_ids: FxHashMap::default() }; + krate = cache_builder.fold_crate(krate); + (krate, cache_builder.impl_ids) + }; + + for (trait_did, dids, impl_) in cx.cache.orphan_trait_impls.drain(..) { + if cx.cache.traits.contains_key(&trait_did) { + for did in dids { + if impl_ids.entry(did).or_default().insert(impl_.def_id()) { + cx.cache.impls.entry(did).or_default().push(impl_.clone()); + } + } + } + } + + krate + } +} + +impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> { + fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> { + if item.item_id.is_local() { + debug!("folding {} \"{:?}\", id {:?}", item.type_(), item.name, item.item_id); + } + + // If this is a stripped module, + // we don't want it or its children in the search index. + let orig_stripped_mod = match *item.kind { + clean::StrippedItem(box clean::ModuleItem(..)) => { + mem::replace(&mut self.cache.stripped_mod, true) + } + _ => self.cache.stripped_mod, + }; + + // If the impl is from a masked crate or references something from a + // masked crate then remove it completely. + if let clean::ImplItem(ref i) = *item.kind { + if self.cache.masked_crates.contains(&item.item_id.krate()) + || i.trait_ + .as_ref() + .map_or(false, |t| self.cache.masked_crates.contains(&t.def_id().krate)) + || i.for_ + .def_id(self.cache) + .map_or(false, |d| self.cache.masked_crates.contains(&d.krate)) + { + return None; + } + } + + // Propagate a trait method's documentation to all implementors of the + // trait. + if let clean::TraitItem(ref t) = *item.kind { + self.cache.traits.entry(item.item_id.expect_def_id()).or_insert_with(|| { + clean::TraitWithExtraInfo { + trait_: t.clone(), + is_notable: item.attrs.has_doc_flag(sym::notable_trait), + } + }); + } + + // Collect all the implementors of traits. + if let clean::ImplItem(ref i) = *item.kind { + if let Some(trait_) = &i.trait_ { + if !i.kind.is_blanket() { + self.cache + .implementors + .entry(trait_.def_id()) + .or_default() + .push(Impl { impl_item: item.clone() }); + } + } + } + + // Index this method for searching later on. + if let Some(ref s) = item.name.or_else(|| { + if item.is_stripped() { + None + } else if let clean::ImportItem(ref i) = *item.kind && + let clean::ImportKind::Simple(s) = i.kind { + Some(s) + } else { + None + } + }) { + let (parent, is_inherent_impl_item) = match *item.kind { + clean::StrippedItem(..) => ((None, None), false), + clean::AssocConstItem(..) | clean::AssocTypeItem(..) + if self + .cache + .parent_stack + .last() + .map_or(false, |parent| parent.is_trait_impl()) => + { + // skip associated items in trait impls + ((None, None), false) + } + clean::TyMethodItem(..) + | clean::TyAssocConstItem(..) + | clean::TyAssocTypeItem(..) + | clean::StructFieldItem(..) + | clean::VariantItem(..) => ( + ( + Some( + self.cache + .parent_stack + .last() + .expect("parent_stack is empty") + .item_id() + .expect_def_id(), + ), + Some(&self.cache.stack[..self.cache.stack.len() - 1]), + ), + false, + ), + clean::MethodItem(..) | clean::AssocConstItem(..) | clean::AssocTypeItem(..) => { + if self.cache.parent_stack.is_empty() { + ((None, None), false) + } else { + let last = self.cache.parent_stack.last().expect("parent_stack is empty 2"); + let did = match &*last { + ParentStackItem::Impl { for_, .. } => for_.def_id(&self.cache), + ParentStackItem::Type(item_id) => item_id.as_def_id(), + }; + let path = match did.and_then(|did| self.cache.paths.get(&did)) { + // The current stack not necessarily has correlation + // for where the type was defined. On the other + // hand, `paths` always has the right + // information if present. + Some(&(ref fqp, _)) => Some(&fqp[..fqp.len() - 1]), + None => None, + }; + ((did, path), true) + } + } + _ => ((None, Some(&*self.cache.stack)), false), + }; + + match parent { + (parent, Some(path)) if is_inherent_impl_item || !self.cache.stripped_mod => { + debug_assert!(!item.is_stripped()); + + // A crate has a module at its root, containing all items, + // which should not be indexed. The crate-item itself is + // inserted later on when serializing the search-index. + if item.item_id.as_def_id().map_or(false, |idx| !idx.is_crate_root()) { + let desc = item.doc_value().map_or_else(String::new, |x| { + short_markdown_summary(x.as_str(), &item.link_names(self.cache)) + }); + self.cache.search_index.push(IndexItem { + ty: item.type_(), + name: s.to_string(), + path: join_with_double_colon(path), + desc, + parent, + parent_idx: None, + search_type: get_function_type_for_search( + &item, + self.tcx, + clean_impl_generics(self.cache.parent_stack.last()).as_ref(), + self.cache, + ), + aliases: item.attrs.get_doc_aliases(), + }); + } + } + (Some(parent), None) if is_inherent_impl_item => { + // We have a parent, but we don't know where they're + // defined yet. Wait for later to index this item. + let impl_generics = clean_impl_generics(self.cache.parent_stack.last()); + self.cache.orphan_impl_items.push(OrphanImplItem { + parent, + item: item.clone(), + impl_generics, + }); + } + _ => {} + } + } + + // Keep track of the fully qualified path for this item. + let pushed = match item.name { + Some(n) if !n.is_empty() => { + self.cache.stack.push(n); + true + } + _ => false, + }; + + match *item.kind { + clean::StructItem(..) + | clean::EnumItem(..) + | clean::TypedefItem(..) + | clean::TraitItem(..) + | clean::TraitAliasItem(..) + | clean::FunctionItem(..) + | clean::ModuleItem(..) + | clean::ForeignFunctionItem(..) + | clean::ForeignStaticItem(..) + | clean::ConstantItem(..) + | clean::StaticItem(..) + | clean::UnionItem(..) + | clean::ForeignTypeItem + | clean::MacroItem(..) + | clean::ProcMacroItem(..) + | clean::VariantItem(..) => { + if !self.cache.stripped_mod { + // Re-exported items mean that the same id can show up twice + // in the rustdoc ast that we're looking at. We know, + // however, that a re-exported item doesn't show up in the + // `public_items` map, so we can skip inserting into the + // paths map if there was already an entry present and we're + // not a public item. + if !self.cache.paths.contains_key(&item.item_id.expect_def_id()) + || self.cache.access_levels.is_public(item.item_id.expect_def_id()) + { + self.cache.paths.insert( + item.item_id.expect_def_id(), + (self.cache.stack.clone(), item.type_()), + ); + } + } + } + clean::PrimitiveItem(..) => { + self.cache + .paths + .insert(item.item_id.expect_def_id(), (self.cache.stack.clone(), item.type_())); + } + + clean::ExternCrateItem { .. } + | clean::ImportItem(..) + | clean::OpaqueTyItem(..) + | clean::ImplItem(..) + | clean::TyMethodItem(..) + | clean::MethodItem(..) + | clean::StructFieldItem(..) + | clean::TyAssocConstItem(..) + | clean::AssocConstItem(..) + | clean::TyAssocTypeItem(..) + | clean::AssocTypeItem(..) + | clean::StrippedItem(..) + | clean::KeywordItem => { + // FIXME: Do these need handling? + // The person writing this comment doesn't know. + // So would rather leave them to an expert, + // as at least the list is better than `_ => {}`. + } + } + + // Maintain the parent stack. + let (item, parent_pushed) = match *item.kind { + clean::TraitItem(..) + | clean::EnumItem(..) + | clean::ForeignTypeItem + | clean::StructItem(..) + | clean::UnionItem(..) + | clean::VariantItem(..) + | clean::ImplItem(..) => { + self.cache.parent_stack.push(ParentStackItem::new(&item)); + (self.fold_item_recur(item), true) + } + _ => (self.fold_item_recur(item), false), + }; + + // Once we've recursively found all the generics, hoard off all the + // implementations elsewhere. + let ret = if let clean::Item { kind: box clean::ImplItem(ref i), .. } = item { + // Figure out the id of this impl. This may map to a + // primitive rather than always to a struct/enum. + // Note: matching twice to restrict the lifetime of the `i` borrow. + let mut dids = FxHashSet::default(); + match i.for_ { + clean::Type::Path { ref path } + | clean::BorrowedRef { type_: box clean::Type::Path { ref path }, .. } => { + dids.insert(path.def_id()); + if let Some(generics) = path.generics() && + let ty::Adt(adt, _) = self.tcx.type_of(path.def_id()).kind() && + adt.is_fundamental() { + for ty in generics { + if let Some(did) = ty.def_id(self.cache) { + dids.insert(did); + } + } + } + } + clean::DynTrait(ref bounds, _) + | clean::BorrowedRef { type_: box clean::DynTrait(ref bounds, _), .. } => { + dids.insert(bounds[0].trait_.def_id()); + } + ref t => { + let did = t + .primitive_type() + .and_then(|t| self.cache.primitive_locations.get(&t).cloned()); + + if let Some(did) = did { + dids.insert(did); + } + } + } + + if let Some(generics) = i.trait_.as_ref().and_then(|t| t.generics()) { + for bound in generics { + if let Some(did) = bound.def_id(self.cache) { + dids.insert(did); + } + } + } + let impl_item = Impl { impl_item: item }; + if impl_item.trait_did().map_or(true, |d| self.cache.traits.contains_key(&d)) { + for did in dids { + if self.impl_ids.entry(did).or_default().insert(impl_item.def_id()) { + self.cache + .impls + .entry(did) + .or_insert_with(Vec::new) + .push(impl_item.clone()); + } + } + } else { + let trait_did = impl_item.trait_did().expect("no trait did"); + self.cache.orphan_trait_impls.push((trait_did, dids, impl_item)); + } + None + } else { + Some(item) + }; + + if pushed { + self.cache.stack.pop().expect("stack already empty"); + } + if parent_pushed { + self.cache.parent_stack.pop().expect("parent stack already empty"); + } + self.cache.stripped_mod = orig_stripped_mod; + ret + } +} + +pub(crate) struct OrphanImplItem { + pub(crate) parent: DefId, + pub(crate) item: clean::Item, + pub(crate) impl_generics: Option<(clean::Type, clean::Generics)>, +} + +/// Information about trait and type parents is tracked while traversing the item tree to build +/// the cache. +/// +/// We don't just store `Item` in there, because `Item` contains the list of children being +/// traversed and it would be wasteful to clone all that. We also need the item id, so just +/// storing `ItemKind` won't work, either. +enum ParentStackItem { + Impl { + for_: clean::Type, + trait_: Option<clean::Path>, + generics: clean::Generics, + kind: clean::ImplKind, + item_id: ItemId, + }, + Type(ItemId), +} + +impl ParentStackItem { + fn new(item: &clean::Item) -> Self { + match &*item.kind { + clean::ItemKind::ImplItem(box clean::Impl { for_, trait_, generics, kind, .. }) => { + ParentStackItem::Impl { + for_: for_.clone(), + trait_: trait_.clone(), + generics: generics.clone(), + kind: kind.clone(), + item_id: item.item_id, + } + } + _ => ParentStackItem::Type(item.item_id), + } + } + fn is_trait_impl(&self) -> bool { + matches!(self, ParentStackItem::Impl { trait_: Some(..), .. }) + } + fn item_id(&self) -> ItemId { + match self { + ParentStackItem::Impl { item_id, .. } => *item_id, + ParentStackItem::Type(item_id) => *item_id, + } + } +} + +fn clean_impl_generics(item: Option<&ParentStackItem>) -> Option<(clean::Type, clean::Generics)> { + if let Some(ParentStackItem::Impl { for_, generics, kind: clean::ImplKind::Normal, .. }) = item + { + Some((for_.clone(), generics.clone())) + } else { + None + } +} |