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use std::mem;
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet};
use rustc_middle::ty::{self, TyCtxt};
use rustc_span::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;
use crate::visit_lib::RustdocEffectiveVisibilities;
/// 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: DefIdMap<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: DefIdMap<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::Trait>,
/// 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 effective visibilities from the privacy check pass.
pub(crate) effective_visibilities: RustdocEffectiveVisibilities,
/// 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,
/// Whether to document hidden items.
/// This is stored in `Cache` so it doesn't need to be passed through all rustdoc functions.
pub(crate) document_hidden: 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, FxIndexSet<clean::ItemLink>>,
/// Cfg that have been hidden via #![doc(cfg_hide(...))]
pub(crate) hidden_cfg: FxHashSet<clean::cfg::Cfg>,
/// Contains the list of `DefId`s which have been inlined. It is used when generating files
/// to check if a stripped item should get its file generated or not: if it's inside a
/// `#[doc(hidden)]` item or a private one and not inlined, it shouldn't get a file.
pub(crate) inlined_items: DefIdSet,
}
/// 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: DefIdMap<DefIdSet>,
tcx: TyCtxt<'tcx>,
}
impl Cache {
pub(crate) fn new(document_private: bool, document_hidden: bool) -> Self {
Cache { document_private, document_hidden, ..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 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: Default::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() {
let is_stripped = matches!(*item.kind, clean::ItemKind::StrippedItem(..));
debug!(
"folding {} (stripped: {is_stripped:?}) \"{:?}\", 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(|| (**t).clone());
}
// Collect all the implementors of traits.
if let clean::ImplItem(ref i) = *item.kind &&
let Some(trait_) = &i.trait_ &&
!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(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 {
// impl Trait for &T { fn method(self); }
//
// When generating a function index with the above shape, we want it
// associated with `T`, not with the primitive reference type. It should
// show up as `T::method`, rather than `reference::method`, in the search
// results page.
for_: clean::Type::BorrowedRef { type_, .. },
..
} => type_.def_id(&self.cache),
ParentStackItem::Impl { for_, .. } => for_.def_id(&self.cache),
ParentStackItem::Type(item_id) => item_id.as_def_id(),
};
let path = 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.
.map(|(fqp, _)| &fqp[..fqp.len() - 1]);
((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 =
short_markdown_summary(&item.doc_value(), &item.link_names(self.cache));
let ty = item.type_();
if ty != ItemType::StructField
|| u16::from_str_radix(s.as_str(), 10).is_err()
{
// In case this is a field from a tuple struct, we don't add it into
// the search index because its name is something like "0", which is
// not useful for rustdoc search.
self.cache.search_index.push(IndexItem {
ty,
name: s,
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(),
deprecation: item.deprecation(self.tcx),
});
}
}
}
(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::TypeAliasItem(..)
| 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
.effective_visibilities
.is_directly_public(self.tcx, 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::TypeAliasItem(..)
| 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()).instantiate_identity().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
}
}