rust/src/librustdoc/formats/cache.rs

489 lines
20 KiB
Rust

use std::cell::RefCell;
use std::collections::BTreeMap;
use std::mem;
use std::path::{Path, PathBuf};
use std::sync::Arc;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
use rustc_middle::middle::privacy::AccessLevels;
use rustc_span::source_map::FileName;
use crate::clean::{self, GetDefId};
use crate::config::RenderInfo;
use crate::fold::DocFolder;
use crate::formats::item_type::ItemType;
use crate::formats::Impl;
use crate::html::render::cache::{extern_location, get_index_search_type, ExternalLocation};
use crate::html::render::IndexItem;
use crate::html::render::{plain_text_summary, shorten};
thread_local!(crate static CACHE_KEY: RefCell<Arc<Cache>> = Default::default());
/// 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 a `Arc` instance and shared among the various
/// rendering threads.
#[derive(Default)]
crate struct Cache {
/// Maps a type ID to all known implementations for that type. This is only
/// recognized for intra-crate `ResolvedPath` types, 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.
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.
crate paths: FxHashMap<DefId, (Vec<String>, ItemType)>,
/// Similar to `paths`, but only holds external paths. This is only used for
/// generating explicit hyperlinks to other crates.
crate external_paths: FxHashMap<DefId, (Vec<String>, 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.
crate exact_paths: FxHashMap<DefId, Vec<String>>,
/// 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.
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
crate implementors: FxHashMap<DefId, Vec<Impl>>,
/// Cache of where external crate documentation can be found.
crate extern_locations: FxHashMap<CrateNum, (String, PathBuf, ExternalLocation)>,
/// Cache of where documentation for primitives can be found.
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.
crate access_levels: AccessLevels<DefId>,
/// The version of the crate being documented, if given from the `--crate-version` flag.
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.
crate document_private: bool,
// Private fields only used when initially crawling a crate to build a cache
stack: Vec<String>,
parent_stack: Vec<DefId>,
parent_is_trait_impl: bool,
stripped_mod: bool,
masked_crates: FxHashSet<CrateNum>,
crate search_index: Vec<IndexItem>,
crate deref_trait_did: Option<DefId>,
crate deref_mut_trait_did: Option<DefId>,
crate owned_box_did: Option<DefId>,
// 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.
crate orphan_impl_items: Vec<(DefId, clean::Item)>,
// 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 spotlight 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)>,
/// Aliases added through `#[doc(alias = "...")]`. Since a few items can have the same alias,
/// we need the alias element to have an array of items.
crate aliases: BTreeMap<String, Vec<usize>>,
}
impl Cache {
crate fn from_krate(
render_info: RenderInfo,
document_private: bool,
extern_html_root_urls: &BTreeMap<String, String>,
dst: &Path,
mut krate: clean::Crate,
) -> (clean::Crate, Cache) {
// Crawl the crate to build various caches used for the output
let RenderInfo {
inlined: _,
external_paths,
exact_paths,
access_levels,
deref_trait_did,
deref_mut_trait_did,
owned_box_did,
..
} = render_info;
let external_paths =
external_paths.into_iter().map(|(k, (v, t))| (k, (v, ItemType::from(t)))).collect();
let mut cache = Cache {
external_paths,
exact_paths,
parent_is_trait_impl: false,
stripped_mod: false,
access_levels,
crate_version: krate.version.take(),
document_private,
traits: krate.external_traits.replace(Default::default()),
deref_trait_did,
deref_mut_trait_did,
owned_box_did,
masked_crates: mem::take(&mut krate.masked_crates),
..Cache::default()
};
// 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 &(n, ref e) in &krate.externs {
let src_root = match e.src {
FileName::Real(ref p) => match p.local_path().parent() {
Some(p) => p.to_path_buf(),
None => PathBuf::new(),
},
_ => PathBuf::new(),
};
let extern_url = extern_html_root_urls.get(&e.name).map(|u| &**u);
cache
.extern_locations
.insert(n, (e.name.clone(), src_root, extern_location(e, extern_url, &dst)));
let did = DefId { krate: n, index: CRATE_DEF_INDEX };
cache.external_paths.insert(did, (vec![e.name.to_string()], ItemType::Module));
}
// Cache where all known primitives have their documentation located.
//
// Favor linking to as local extern as possible, so iterate all crates in
// reverse topological order.
for &(_, ref e) in krate.externs.iter().rev() {
for &(def_id, prim, _) in &e.primitives {
cache.primitive_locations.insert(prim, def_id);
}
}
for &(def_id, prim, _) in &krate.primitives {
cache.primitive_locations.insert(prim, def_id);
}
cache.stack.push(krate.name.clone());
krate = cache.fold_crate(krate);
for (trait_did, dids, impl_) in cache.orphan_trait_impls.drain(..) {
if cache.traits.contains_key(&trait_did) {
for did in dids {
cache.impls.entry(did).or_default().push(impl_.clone());
}
}
}
(krate, cache)
}
}
impl DocFolder for Cache {
fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> {
if item.def_id.is_local() {
debug!("folding {} \"{:?}\", id {:?}", item.type_(), item.name, item.def_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.stripped_mod, true)
}
_ => self.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.masked_crates.contains(&item.def_id.krate)
|| i.trait_.def_id().map_or(false, |d| self.masked_crates.contains(&d.krate))
|| i.for_.def_id().map_or(false, |d| self.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.traits.entry(item.def_id).or_insert_with(|| t.clone());
}
// Collect all the implementors of traits.
if let clean::ImplItem(ref i) = item.kind {
if let Some(did) = i.trait_.def_id() {
if i.blanket_impl.is_none() {
self.implementors
.entry(did)
.or_default()
.push(Impl { impl_item: item.clone() });
}
}
}
// Index this method for searching later on.
if let Some(ref s) = item.name {
let (parent, is_inherent_impl_item) = match item.kind {
clean::StrippedItem(..) => ((None, None), false),
clean::AssocConstItem(..) | clean::TypedefItem(_, true)
if self.parent_is_trait_impl =>
{
// skip associated items in trait impls
((None, None), false)
}
clean::AssocTypeItem(..)
| clean::TyMethodItem(..)
| clean::StructFieldItem(..)
| clean::VariantItem(..) => (
(
Some(*self.parent_stack.last().expect("parent_stack is empty")),
Some(&self.stack[..self.stack.len() - 1]),
),
false,
),
clean::MethodItem(..) | clean::AssocConstItem(..) => {
if self.parent_stack.is_empty() {
((None, None), false)
} else {
let last = self.parent_stack.last().expect("parent_stack is empty 2");
let did = *last;
let path = match self.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,
ItemType::Trait
| ItemType::Struct
| ItemType::Union
| ItemType::Enum,
)) => Some(&fqp[..fqp.len() - 1]),
Some(..) => Some(&*self.stack),
None => None,
};
((Some(*last), path), true)
}
}
_ => ((None, Some(&*self.stack)), false),
};
match parent {
(parent, Some(path)) if is_inherent_impl_item || !self.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.def_id.index != CRATE_DEF_INDEX {
self.search_index.push(IndexItem {
ty: item.type_(),
name: s.to_string(),
path: path.join("::"),
desc: shorten(plain_text_summary(item.doc_value())),
parent,
parent_idx: None,
search_type: get_index_search_type(&item),
});
for alias in item.attrs.get_doc_aliases() {
self.aliases
.entry(alias.to_lowercase())
.or_insert(Vec::new())
.push(self.search_index.len() - 1);
}
}
}
(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.
self.orphan_impl_items.push((parent, item.clone()));
}
_ => {}
}
}
// Keep track of the fully qualified path for this item.
let pushed = match item.name {
Some(ref n) if !n.is_empty() => {
self.stack.push(n.to_string());
true
}
_ => false,
};
match item.kind {
clean::StructItem(..)
| clean::EnumItem(..)
| clean::TypedefItem(..)
| clean::TraitItem(..)
| clean::FunctionItem(..)
| clean::ModuleItem(..)
| clean::ForeignFunctionItem(..)
| clean::ForeignStaticItem(..)
| clean::ConstantItem(..)
| clean::StaticItem(..)
| clean::UnionItem(..)
| clean::ForeignTypeItem
| clean::MacroItem(..)
| clean::ProcMacroItem(..)
| clean::VariantItem(..)
if !self.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.paths.contains_key(&item.def_id)
|| self.access_levels.is_public(item.def_id)
{
self.paths.insert(item.def_id, (self.stack.clone(), item.type_()));
}
}
clean::PrimitiveItem(..) => {
self.paths.insert(item.def_id, (self.stack.clone(), item.type_()));
}
_ => {}
}
// Maintain the parent stack
let orig_parent_is_trait_impl = self.parent_is_trait_impl;
let parent_pushed = match item.kind {
clean::TraitItem(..)
| clean::EnumItem(..)
| clean::ForeignTypeItem
| clean::StructItem(..)
| clean::UnionItem(..)
| clean::VariantItem(..) => {
self.parent_stack.push(item.def_id);
self.parent_is_trait_impl = false;
true
}
clean::ImplItem(ref i) => {
self.parent_is_trait_impl = i.trait_.is_some();
match i.for_ {
clean::ResolvedPath { did, .. } => {
self.parent_stack.push(did);
true
}
ref t => {
let prim_did = t
.primitive_type()
.and_then(|t| self.primitive_locations.get(&t).cloned());
match prim_did {
Some(did) => {
self.parent_stack.push(did);
true
}
None => false,
}
}
}
}
_ => false,
};
// Once we've recursively found all the generics, hoard off all the
// implementations elsewhere.
let ret = self.fold_item_recur(item).and_then(|item| {
if let clean::Item { kind: clean::ImplItem(_), .. } = 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();
if let clean::Item { kind: clean::ImplItem(ref i), .. } = item {
match i.for_ {
clean::ResolvedPath { did, .. }
| clean::BorrowedRef {
type_: box clean::ResolvedPath { did, .. }, ..
} => {
dids.insert(did);
}
ref t => {
let did = t
.primitive_type()
.and_then(|t| self.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() {
dids.insert(did);
}
}
}
} else {
unreachable!()
};
let impl_item = Impl { impl_item: item };
if impl_item.trait_did().map_or(true, |d| self.traits.contains_key(&d)) {
for did in dids {
self.impls.entry(did).or_insert(vec![]).push(impl_item.clone());
}
} else {
let trait_did = impl_item.trait_did().expect("no trait did");
self.orphan_trait_impls.push((trait_did, dids, impl_item));
}
None
} else {
Some(item)
}
});
if pushed {
self.stack.pop().expect("stack already empty");
}
if parent_pushed {
self.parent_stack.pop().expect("parent stack already empty");
}
self.stripped_mod = orig_stripped_mod;
self.parent_is_trait_impl = orig_parent_is_trait_impl;
ret
}
}
crate fn cache() -> Arc<Cache> {
CACHE_KEY.with(|c| c.borrow().clone())
}