rust/src/librustdoc/html/render/cache.rs
2021-11-10 11:13:52 +01:00

418 lines
15 KiB
Rust

use std::collections::hash_map::Entry;
use std::collections::BTreeMap;
use rustc_data_structures::fx::FxHashMap;
use rustc_middle::ty::TyCtxt;
use rustc_span::symbol::Symbol;
use serde::ser::{Serialize, SerializeStruct, Serializer};
use crate::clean;
use crate::clean::types::{FnDecl, FnRetTy, GenericBound, Generics, Type, WherePredicate};
use crate::formats::cache::Cache;
use crate::formats::item_type::ItemType;
use crate::html::markdown::short_markdown_summary;
use crate::html::render::{IndexItem, IndexItemFunctionType, RenderType, TypeWithKind};
/// Indicates where an external crate can be found.
crate enum ExternalLocation {
/// Remote URL root of the external crate
Remote(String),
/// This external crate can be found in the local doc/ folder
Local,
/// The external crate could not be found.
Unknown,
}
/// Builds the search index from the collected metadata
crate fn build_index<'tcx>(krate: &clean::Crate, cache: &mut Cache, tcx: TyCtxt<'tcx>) -> String {
let mut defid_to_pathid = FxHashMap::default();
let mut crate_items = Vec::with_capacity(cache.search_index.len());
let mut crate_paths = vec![];
// Attach all orphan items to the type's definition if the type
// has since been learned.
for &(did, ref item) in &cache.orphan_impl_items {
if let Some(&(ref fqp, _)) = cache.paths.get(&did) {
let desc = item
.doc_value()
.map_or_else(String::new, |s| short_markdown_summary(&s, &item.link_names(cache)));
cache.search_index.push(IndexItem {
ty: item.type_(),
name: item.name.unwrap().to_string(),
path: fqp[..fqp.len() - 1].join("::"),
desc,
parent: Some(did),
parent_idx: None,
search_type: get_index_search_type(item, tcx),
aliases: item.attrs.get_doc_aliases(),
});
}
}
let crate_doc = krate
.module
.doc_value()
.map_or_else(String::new, |s| short_markdown_summary(&s, &krate.module.link_names(cache)));
let Cache { ref mut search_index, ref paths, .. } = *cache;
// 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.
let mut aliases: BTreeMap<String, Vec<usize>> = BTreeMap::new();
// Sort search index items. This improves the compressibility of the search index.
search_index.sort_unstable_by(|k1, k2| {
// `sort_unstable_by_key` produces lifetime errors
let k1 = (&k1.path, &k1.name, &k1.ty, &k1.parent);
let k2 = (&k2.path, &k2.name, &k2.ty, &k2.parent);
std::cmp::Ord::cmp(&k1, &k2)
});
// Set up alias indexes.
for (i, item) in search_index.iter().enumerate() {
for alias in &item.aliases[..] {
aliases.entry(alias.to_lowercase()).or_insert_with(Vec::new).push(i);
}
}
// Reduce `DefId` in paths into smaller sequential numbers,
// and prune the paths that do not appear in the index.
let mut lastpath = String::new();
let mut lastpathid = 0usize;
for item in search_index {
item.parent_idx = item.parent.and_then(|defid| match defid_to_pathid.entry(defid) {
Entry::Occupied(entry) => Some(*entry.get()),
Entry::Vacant(entry) => {
let pathid = lastpathid;
entry.insert(pathid);
lastpathid += 1;
if let Some(&(ref fqp, short)) = paths.get(&defid) {
crate_paths.push((short, fqp.last().unwrap().clone()));
Some(pathid)
} else {
None
}
}
});
// Omit the parent path if it is same to that of the prior item.
if lastpath == item.path {
item.path.clear();
} else {
lastpath = item.path.clone();
}
crate_items.push(&*item);
}
struct CrateData<'a> {
doc: String,
items: Vec<&'a IndexItem>,
paths: Vec<(ItemType, String)>,
// The String is alias name and the vec is the list of the elements with this alias.
//
// To be noted: the `usize` elements are indexes to `items`.
aliases: &'a BTreeMap<String, Vec<usize>>,
}
impl<'a> Serialize for CrateData<'a> {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
let has_aliases = !self.aliases.is_empty();
let mut crate_data =
serializer.serialize_struct("CrateData", if has_aliases { 9 } else { 8 })?;
crate_data.serialize_field("doc", &self.doc)?;
crate_data.serialize_field(
"t",
&self.items.iter().map(|item| &item.ty).collect::<Vec<_>>(),
)?;
crate_data.serialize_field(
"n",
&self.items.iter().map(|item| &item.name).collect::<Vec<_>>(),
)?;
crate_data.serialize_field(
"q",
&self.items.iter().map(|item| &item.path).collect::<Vec<_>>(),
)?;
crate_data.serialize_field(
"d",
&self.items.iter().map(|item| &item.desc).collect::<Vec<_>>(),
)?;
crate_data.serialize_field(
"i",
&self
.items
.iter()
.map(|item| {
assert_eq!(
item.parent.is_some(),
item.parent_idx.is_some(),
"`{}` is missing idx",
item.name
);
item.parent_idx.map(|x| x + 1).unwrap_or(0)
})
.collect::<Vec<_>>(),
)?;
crate_data.serialize_field(
"f",
&self.items.iter().map(|item| &item.search_type).collect::<Vec<_>>(),
)?;
crate_data.serialize_field("p", &self.paths)?;
if has_aliases {
crate_data.serialize_field("a", &self.aliases)?;
}
crate_data.end()
}
}
// Collect the index into a string
format!(
r#""{}":{}"#,
krate.name(tcx),
serde_json::to_string(&CrateData {
doc: crate_doc,
items: crate_items,
paths: crate_paths,
aliases: &aliases,
})
.expect("failed serde conversion")
// All these `replace` calls are because we have to go through JS string for JSON content.
.replace(r"\", r"\\")
.replace("'", r"\'")
// We need to escape double quotes for the JSON.
.replace("\\\"", "\\\\\"")
)
}
crate fn get_index_search_type<'tcx>(
item: &clean::Item,
tcx: TyCtxt<'tcx>,
) -> Option<IndexItemFunctionType> {
let (mut inputs, mut output) = match *item.kind {
clean::FunctionItem(ref f) => get_all_types(&f.generics, &f.decl, tcx),
clean::MethodItem(ref m, _) => get_all_types(&m.generics, &m.decl, tcx),
clean::TyMethodItem(ref m) => get_all_types(&m.generics, &m.decl, tcx),
_ => return None,
};
inputs.retain(|a| a.ty.name.is_some());
output.retain(|a| a.ty.name.is_some());
let output = if output.is_empty() { None } else { Some(output) };
Some(IndexItemFunctionType { inputs, output })
}
fn get_index_type(clean_type: &clean::Type, generics: Vec<TypeWithKind>) -> RenderType {
RenderType {
name: get_index_type_name(clean_type, true).map(|s| s.as_str().to_ascii_lowercase()),
generics: if generics.is_empty() { None } else { Some(generics) },
}
}
fn get_index_type_name(clean_type: &clean::Type, accept_generic: bool) -> Option<Symbol> {
match *clean_type {
clean::ResolvedPath { ref path, .. } => {
let path_segment = path.segments.last().unwrap();
Some(path_segment.name)
}
clean::DynTrait(ref bounds, _) => {
let path = &bounds[0].trait_;
Some(path.segments.last().unwrap().name)
}
clean::Generic(s) if accept_generic => Some(s),
clean::Primitive(ref p) => Some(p.as_sym()),
clean::BorrowedRef { ref type_, .. } => get_index_type_name(type_, accept_generic),
clean::Generic(_)
| clean::BareFunction(_)
| clean::Tuple(_)
| clean::Slice(_)
| clean::Array(_, _)
| clean::RawPointer(_, _)
| clean::QPath { .. }
| clean::Infer
| clean::ImplTrait(_) => None,
}
}
/// The point of this function is to replace bounds with types.
///
/// i.e. `[T, U]` when you have the following bounds: `T: Display, U: Option<T>` will return
/// `[Display, Option]` (we just returns the list of the types, we don't care about the
/// wrapped types in here).
crate fn get_real_types<'tcx>(
generics: &Generics,
arg: &Type,
tcx: TyCtxt<'tcx>,
recurse: usize,
res: &mut Vec<TypeWithKind>,
) {
fn insert_ty(
res: &mut Vec<TypeWithKind>,
tcx: TyCtxt<'_>,
ty: Type,
mut generics: Vec<TypeWithKind>,
) {
let is_full_generic = ty.is_full_generic();
if is_full_generic {
if generics.is_empty() {
// This is a type parameter with no trait bounds (for example: `T` in
// `fn f<T>(p: T)`, so not useful for the rustdoc search because we would end up
// with an empty type with an empty name. Let's just discard it.
return;
} else if generics.len() == 1 {
// In this case, no need to go through an intermediate state if the type parameter
// contains only one trait bound.
//
// For example:
//
// `fn foo<T: Display>(r: Option<T>) {}`
//
// In this case, it would contain:
//
// ```
// [{
// name: "option",
// generics: [{
// name: "",
// generics: [
// name: "Display",
// generics: []
// }]
// }]
// }]
// ```
//
// After removing the intermediate (unnecessary) type parameter, it'll become:
//
// ```
// [{
// name: "option",
// generics: [{
// name: "Display",
// generics: []
// }]
// }]
// ```
//
// To be noted that it can work if there is ONLY ONE trait bound, otherwise we still
// need to keep it as is!
res.push(generics.pop().unwrap());
return;
}
}
let mut index_ty = get_index_type(&ty, generics);
if index_ty.name.as_ref().map(|s| s.is_empty()).unwrap_or(true) {
return;
}
if is_full_generic {
// We remove the name of the full generic because we have no use for it.
index_ty.name = Some(String::new());
res.push(TypeWithKind::from((index_ty, ItemType::Generic)));
} else if let Some(kind) = ty.def_id_no_primitives().map(|did| tcx.def_kind(did).into()) {
res.push(TypeWithKind::from((index_ty, kind)));
} else if ty.is_primitive() {
// This is a primitive, let's store it as such.
res.push(TypeWithKind::from((index_ty, ItemType::Primitive)));
}
}
if recurse >= 10 {
// FIXME: remove this whole recurse thing when the recursion bug is fixed
return;
}
if let Type::Generic(arg_s) = *arg {
if let Some(where_pred) = generics.where_predicates.iter().find(|g| match g {
WherePredicate::BoundPredicate { ty, .. } => {
ty.def_id_no_primitives() == arg.def_id_no_primitives()
}
_ => false,
}) {
let mut ty_generics = Vec::new();
let bounds = where_pred.get_bounds().unwrap_or_else(|| &[]);
for bound in bounds.iter() {
if let GenericBound::TraitBound(poly_trait, _) = bound {
for x in poly_trait.generic_params.iter() {
if !x.is_type() {
continue;
}
if let Some(ty) = x.get_type() {
get_real_types(generics, &ty, tcx, recurse + 1, &mut ty_generics);
}
}
}
}
insert_ty(res, tcx, arg.clone(), ty_generics);
}
if let Some(bound) = generics.params.iter().find(|g| g.is_type() && g.name == arg_s) {
let mut ty_generics = Vec::new();
for bound in bound.get_bounds().unwrap_or(&[]) {
if let Some(path) = bound.get_trait_path() {
let ty = Type::ResolvedPath { did: path.def_id(), path };
get_real_types(generics, &ty, tcx, recurse + 1, &mut ty_generics);
}
}
insert_ty(res, tcx, arg.clone(), ty_generics);
}
} else {
let mut ty_generics = Vec::new();
if let Some(arg_generics) = arg.generics() {
for gen in arg_generics.iter() {
get_real_types(generics, gen, tcx, recurse + 1, &mut ty_generics);
}
}
insert_ty(res, tcx, arg.clone(), ty_generics);
}
}
/// Return the full list of types when bounds have been resolved.
///
/// i.e. `fn foo<A: Display, B: Option<A>>(x: u32, y: B)` will return
/// `[u32, Display, Option]`.
crate fn get_all_types<'tcx>(
generics: &Generics,
decl: &FnDecl,
tcx: TyCtxt<'tcx>,
) -> (Vec<TypeWithKind>, Vec<TypeWithKind>) {
let mut all_types = Vec::new();
for arg in decl.inputs.values.iter() {
if arg.type_.is_self_type() {
continue;
}
// FIXME: performance wise, it'd be much better to move `args` declaration outside of the
// loop and replace this line with `args.clear()`.
let mut args = Vec::new();
get_real_types(generics, &arg.type_, tcx, 0, &mut args);
if !args.is_empty() {
// FIXME: once back to performance improvements, replace this line with:
// `all_types.extend(args.drain(..));`.
all_types.extend(args);
} else {
if let Some(kind) = arg.type_.def_id_no_primitives().map(|did| tcx.def_kind(did).into())
{
all_types.push(TypeWithKind::from((get_index_type(&arg.type_, vec![]), kind)));
}
}
}
let mut ret_types = Vec::new();
match decl.output {
FnRetTy::Return(ref return_type) => {
get_real_types(generics, return_type, tcx, 0, &mut ret_types);
if ret_types.is_empty() {
if let Some(kind) =
return_type.def_id_no_primitives().map(|did| tcx.def_kind(did).into())
{
ret_types.push(TypeWithKind::from((get_index_type(return_type, vec![]), kind)));
}
}
}
_ => {}
};
(all_types, ret_types)
}