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android / toolchain / rustc / refs/heads/main / . / src / librustdoc / html / render / mod.rs
blob: 399730a01c82fa35f885e6001fe18fe5e695da70 [file] [log] [blame] [edit]
//! Rustdoc's HTML rendering module.
//!
//! This modules contains the bulk of the logic necessary for rendering a
//! rustdoc `clean::Crate` instance to a set of static HTML pages. This
//! rendering process is largely driven by the `format!` syntax extension to
//! perform all I/O into files and streams.
//!
//! The rendering process is largely driven by the `Context` and `Cache`
//! structures. The cache is pre-populated by crawling the crate in question,
//! and then it is shared among the various rendering threads. The cache is meant
//! to be a fairly large structure not implementing `Clone` (because it's shared
//! among threads). The context, however, should be a lightweight structure. This
//! is cloned per-thread and contains information about what is currently being
//! rendered.
//!
//! In order to speed up rendering (mostly because of markdown rendering), the
//! rendering process has been parallelized. This parallelization is only
//! exposed through the `crate` method on the context, and then also from the
//! fact that the shared cache is stored in TLS (and must be accessed as such).
//!
//! In addition to rendering the crate itself, this module is also responsible
//! for creating the corresponding search index and source file renderings.
//! These threads are not parallelized (they haven't been a bottleneck yet), and
//! both occur before the crate is rendered.
pub(crate) mod search_index;
#[cfg(test)]
mod tests;
mod context;
mod ordered_json;
mod print_item;
pub(crate) mod sidebar;
mod sorted_template;
mod span_map;
mod type_layout;
mod write_shared;
use std::collections::VecDeque;
use std::fmt::{self, Write};
use std::iter::Peekable;
use std::path::PathBuf;
use std::rc::Rc;
use std::{fs, str};
use rinja::Template;
use rustc_attr::{ConstStability, DeprecatedSince, Deprecation, StabilityLevel, StableSince};
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_hir::Mutability;
use rustc_hir::def_id::{DefId, DefIdSet};
use rustc_middle::ty::print::PrintTraitRefExt;
use rustc_middle::ty::{self, TyCtxt};
use rustc_session::RustcVersion;
use rustc_span::symbol::{Symbol, sym};
use rustc_span::{BytePos, DUMMY_SP, FileName, RealFileName};
use serde::ser::SerializeMap;
use serde::{Serialize, Serializer};
use tracing::{debug, info};
pub(crate) use self::context::*;
pub(crate) use self::span_map::{LinkFromSrc, collect_spans_and_sources};
pub(crate) use self::write_shared::*;
use crate::clean::{self, ItemId, RenderedLink};
use crate::error::Error;
use crate::formats::Impl;
use crate::formats::cache::Cache;
use crate::formats::item_type::ItemType;
use crate::html::escape::Escape;
use crate::html::format::{
Buffer, Ending, HrefError, PrintWithSpace, display_fn, href, join_with_double_colon,
print_abi_with_space, print_constness_with_space, print_default_space, print_generic_bounds,
print_where_clause, visibility_print_with_space,
};
use crate::html::markdown::{
HeadingOffset, IdMap, Markdown, MarkdownItemInfo, MarkdownSummaryLine,
};
use crate::html::static_files::SCRAPE_EXAMPLES_HELP_MD;
use crate::html::{highlight, sources};
use crate::scrape_examples::{CallData, CallLocation};
use crate::{DOC_RUST_LANG_ORG_CHANNEL, try_none};
pub(crate) fn ensure_trailing_slash(v: &str) -> impl fmt::Display + '_ {
crate::html::format::display_fn(move |f| {
if !v.ends_with('/') && !v.is_empty() { write!(f, "{v}/") } else { f.write_str(v) }
})
}
/// Specifies whether rendering directly implemented trait items or ones from a certain Deref
/// impl.
pub(crate) enum AssocItemRender<'a> {
All,
DerefFor { trait_: &'a clean::Path, type_: &'a clean::Type, deref_mut_: bool },
}
/// For different handling of associated items from the Deref target of a type rather than the type
/// itself.
#[derive(Copy, Clone, PartialEq)]
pub(crate) enum RenderMode {
Normal,
ForDeref { mut_: bool },
}
// Helper structs for rendering items/sidebars and carrying along contextual
// information
/// Struct representing one entry in the JS search index. These are all emitted
/// by hand to a large JS file at the end of cache-creation.
#[derive(Debug)]
pub(crate) struct IndexItem {
pub(crate) ty: ItemType,
pub(crate) defid: Option<DefId>,
pub(crate) name: Symbol,
pub(crate) path: String,
pub(crate) desc: String,
pub(crate) parent: Option<DefId>,
pub(crate) parent_idx: Option<isize>,
pub(crate) exact_path: Option<String>,
pub(crate) impl_id: Option<DefId>,
pub(crate) search_type: Option<IndexItemFunctionType>,
pub(crate) aliases: Box<[Symbol]>,
pub(crate) deprecation: Option<Deprecation>,
}
/// A type used for the search index.
#[derive(Debug, Eq, PartialEq)]
pub(crate) struct RenderType {
id: Option<RenderTypeId>,
generics: Option<Vec<RenderType>>,
bindings: Option<Vec<(RenderTypeId, Vec<RenderType>)>>,
}
impl RenderType {
// Types are rendered as lists of lists, because that's pretty compact.
// The contents of the lists are always integers in self-terminating hex
// form, handled by `RenderTypeId::write_to_string`, so no commas are
// needed to separate the items.
pub fn write_to_string(&self, string: &mut String) {
fn write_optional_id(id: Option<RenderTypeId>, string: &mut String) {
// 0 is a sentinel, everything else is one-indexed
match id {
Some(id) => id.write_to_string(string),
None => string.push('`'),
}
}
// Either just the type id, or `{type, generics, bindings?}`
// where generics is a list of types,
// and bindings is a list of `{id, typelist}` pairs.
if self.generics.is_some() || self.bindings.is_some() {
string.push('{');
write_optional_id(self.id, string);
string.push('{');
for generic in &self.generics.as_deref().unwrap_or_default()[..] {
generic.write_to_string(string);
}
string.push('}');
if self.bindings.is_some() {
string.push('{');
for binding in &self.bindings.as_deref().unwrap_or_default()[..] {
string.push('{');
binding.0.write_to_string(string);
string.push('{');
for constraint in &binding.1[..] {
constraint.write_to_string(string);
}
string.push_str("}}");
}
string.push('}');
}
string.push('}');
} else {
write_optional_id(self.id, string);
}
}
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub(crate) enum RenderTypeId {
DefId(DefId),
Primitive(clean::PrimitiveType),
AssociatedType(Symbol),
Index(isize),
Mut,
}
impl RenderTypeId {
pub fn write_to_string(&self, string: &mut String) {
let id: i32 = match &self {
// 0 is a sentinel, everything else is one-indexed
// concrete type
RenderTypeId::Index(idx) if *idx >= 0 => (idx + 1isize).try_into().unwrap(),
// generic type parameter
RenderTypeId::Index(idx) => (*idx).try_into().unwrap(),
_ => panic!("must convert render types to indexes before serializing"),
};
search_index::encode::write_vlqhex_to_string(id, string);
}
}
/// Full type of functions/methods in the search index.
#[derive(Debug, Eq, PartialEq)]
pub(crate) struct IndexItemFunctionType {
inputs: Vec<RenderType>,
output: Vec<RenderType>,
where_clause: Vec<Vec<RenderType>>,
}
impl IndexItemFunctionType {
pub fn write_to_string<'a>(
&'a self,
string: &mut String,
backref_queue: &mut VecDeque<&'a IndexItemFunctionType>,
) {
assert!(backref_queue.len() <= 16);
// If we couldn't figure out a type, just write 0,
// which is encoded as `` ` `` (see RenderTypeId::write_to_string).
let has_missing = self
.inputs
.iter()
.chain(self.output.iter())
.any(|i| i.id.is_none() && i.generics.is_none());
if has_missing {
string.push('`');
} else if let Some(idx) = backref_queue.iter().position(|other| *other == self) {
// The backref queue has 16 items, so backrefs use
// a single hexit, disjoint from the ones used for numbers.
string.push(
char::try_from('0' as u32 + u32::try_from(idx).unwrap())
.expect("last possible value is '?'"),
);
} else {
backref_queue.push_front(self);
if backref_queue.len() > 16 {
backref_queue.pop_back();
}
string.push('{');
match &self.inputs[..] {
[one] if one.generics.is_none() && one.bindings.is_none() => {
one.write_to_string(string);
}
_ => {
string.push('{');
for item in &self.inputs[..] {
item.write_to_string(string);
}
string.push('}');
}
}
match &self.output[..] {
[] if self.where_clause.is_empty() => {}
[one] if one.generics.is_none() && one.bindings.is_none() => {
one.write_to_string(string);
}
_ => {
string.push('{');
for item in &self.output[..] {
item.write_to_string(string);
}
string.push('}');
}
}
for constraint in &self.where_clause {
if let [one] = &constraint[..]
&& one.generics.is_none()
&& one.bindings.is_none()
{
one.write_to_string(string);
} else {
string.push('{');
for item in &constraint[..] {
item.write_to_string(string);
}
string.push('}');
}
}
string.push('}');
}
}
}
#[derive(Debug, Clone)]
pub(crate) struct StylePath {
/// The path to the theme
pub(crate) path: PathBuf,
}
impl StylePath {
pub(crate) fn basename(&self) -> Result<String, Error> {
Ok(try_none!(try_none!(self.path.file_stem(), &self.path).to_str(), &self.path).to_string())
}
}
#[derive(Debug, Eq, PartialEq, Hash)]
struct ItemEntry {
url: String,
name: String,
}
impl ItemEntry {
fn new(mut url: String, name: String) -> ItemEntry {
while url.starts_with('/') {
url.remove(0);
}
ItemEntry { url, name }
}
}
impl ItemEntry {
pub(crate) fn print(&self) -> impl fmt::Display + '_ {
crate::html::format::display_fn(move |f| {
write!(f, "<a href=\"{}\">{}</a>", self.url, Escape(&self.name))
})
}
}
impl PartialOrd for ItemEntry {
fn partial_cmp(&self, other: &ItemEntry) -> Option<::std::cmp::Ordering> {
Some(self.cmp(other))
}
}
impl Ord for ItemEntry {
fn cmp(&self, other: &ItemEntry) -> ::std::cmp::Ordering {
self.name.cmp(&other.name)
}
}
#[derive(Debug)]
struct AllTypes {
structs: FxIndexSet<ItemEntry>,
enums: FxIndexSet<ItemEntry>,
unions: FxIndexSet<ItemEntry>,
primitives: FxIndexSet<ItemEntry>,
traits: FxIndexSet<ItemEntry>,
macros: FxIndexSet<ItemEntry>,
functions: FxIndexSet<ItemEntry>,
type_aliases: FxIndexSet<ItemEntry>,
statics: FxIndexSet<ItemEntry>,
constants: FxIndexSet<ItemEntry>,
attribute_macros: FxIndexSet<ItemEntry>,
derive_macros: FxIndexSet<ItemEntry>,
trait_aliases: FxIndexSet<ItemEntry>,
}
impl AllTypes {
fn new() -> AllTypes {
let new_set = |cap| FxIndexSet::with_capacity_and_hasher(cap, Default::default());
AllTypes {
structs: new_set(100),
enums: new_set(100),
unions: new_set(100),
primitives: new_set(26),
traits: new_set(100),
macros: new_set(100),
functions: new_set(100),
type_aliases: new_set(100),
statics: new_set(100),
constants: new_set(100),
attribute_macros: new_set(100),
derive_macros: new_set(100),
trait_aliases: new_set(100),
}
}
fn append(&mut self, item_name: String, item_type: &ItemType) {
let mut url: Vec<_> = item_name.split("::").skip(1).collect();
if let Some(name) = url.pop() {
let new_url = format!("{}/{item_type}.{name}.html", url.join("/"));
url.push(name);
let name = url.join("::");
match *item_type {
ItemType::Struct => self.structs.insert(ItemEntry::new(new_url, name)),
ItemType::Enum => self.enums.insert(ItemEntry::new(new_url, name)),
ItemType::Union => self.unions.insert(ItemEntry::new(new_url, name)),
ItemType::Primitive => self.primitives.insert(ItemEntry::new(new_url, name)),
ItemType::Trait => self.traits.insert(ItemEntry::new(new_url, name)),
ItemType::Macro => self.macros.insert(ItemEntry::new(new_url, name)),
ItemType::Function => self.functions.insert(ItemEntry::new(new_url, name)),
ItemType::TypeAlias => self.type_aliases.insert(ItemEntry::new(new_url, name)),
ItemType::Static => self.statics.insert(ItemEntry::new(new_url, name)),
ItemType::Constant => self.constants.insert(ItemEntry::new(new_url, name)),
ItemType::ProcAttribute => {
self.attribute_macros.insert(ItemEntry::new(new_url, name))
}
ItemType::ProcDerive => self.derive_macros.insert(ItemEntry::new(new_url, name)),
ItemType::TraitAlias => self.trait_aliases.insert(ItemEntry::new(new_url, name)),
_ => true,
};
}
}
fn item_sections(&self) -> FxHashSet<ItemSection> {
let mut sections = FxHashSet::default();
if !self.structs.is_empty() {
sections.insert(ItemSection::Structs);
}
if !self.enums.is_empty() {
sections.insert(ItemSection::Enums);
}
if !self.unions.is_empty() {
sections.insert(ItemSection::Unions);
}
if !self.primitives.is_empty() {
sections.insert(ItemSection::PrimitiveTypes);
}
if !self.traits.is_empty() {
sections.insert(ItemSection::Traits);
}
if !self.macros.is_empty() {
sections.insert(ItemSection::Macros);
}
if !self.functions.is_empty() {
sections.insert(ItemSection::Functions);
}
if !self.type_aliases.is_empty() {
sections.insert(ItemSection::TypeAliases);
}
if !self.statics.is_empty() {
sections.insert(ItemSection::Statics);
}
if !self.constants.is_empty() {
sections.insert(ItemSection::Constants);
}
if !self.attribute_macros.is_empty() {
sections.insert(ItemSection::AttributeMacros);
}
if !self.derive_macros.is_empty() {
sections.insert(ItemSection::DeriveMacros);
}
if !self.trait_aliases.is_empty() {
sections.insert(ItemSection::TraitAliases);
}
sections
}
fn print(self, f: &mut Buffer) {
fn print_entries(f: &mut Buffer, e: &FxIndexSet<ItemEntry>, kind: ItemSection) {
if !e.is_empty() {
let mut e: Vec<&ItemEntry> = e.iter().collect();
e.sort();
write!(
f,
"<h3 id=\"{id}\">{title}</h3><ul class=\"all-items\">",
id = kind.id(),
title = kind.name(),
);
for s in e.iter() {
write!(f, "<li>{}</li>", s.print());
}
f.write_str("</ul>");
}
}
f.write_str("<h1>List of all items</h1>");
// Note: print_entries does not escape the title, because we know the current set of titles
// doesn't require escaping.
print_entries(f, &self.structs, ItemSection::Structs);
print_entries(f, &self.enums, ItemSection::Enums);
print_entries(f, &self.unions, ItemSection::Unions);
print_entries(f, &self.primitives, ItemSection::PrimitiveTypes);
print_entries(f, &self.traits, ItemSection::Traits);
print_entries(f, &self.macros, ItemSection::Macros);
print_entries(f, &self.attribute_macros, ItemSection::AttributeMacros);
print_entries(f, &self.derive_macros, ItemSection::DeriveMacros);
print_entries(f, &self.functions, ItemSection::Functions);
print_entries(f, &self.type_aliases, ItemSection::TypeAliases);
print_entries(f, &self.trait_aliases, ItemSection::TraitAliases);
print_entries(f, &self.statics, ItemSection::Statics);
print_entries(f, &self.constants, ItemSection::Constants);
}
}
fn scrape_examples_help(shared: &SharedContext<'_>) -> String {
let mut content = SCRAPE_EXAMPLES_HELP_MD.to_owned();
content.push_str(&format!(
"## More information\n\n\
If you want more information about this feature, please read the [corresponding chapter in \
the Rustdoc book]({DOC_RUST_LANG_ORG_CHANNEL}/rustdoc/scraped-examples.html)."
));
let mut ids = IdMap::default();
format!(
"<div class=\"main-heading\">\
<h1>About scraped examples</h1>\
</div>\
<div>{}</div>",
Markdown {
content: &content,
links: &[],
ids: &mut ids,
error_codes: shared.codes,
edition: shared.edition(),
playground: &shared.playground,
heading_offset: HeadingOffset::H1,
}
.into_string()
)
}
fn document<'a, 'cx: 'a>(
cx: &'a mut Context<'cx>,
item: &'a clean::Item,
parent: Option<&'a clean::Item>,
heading_offset: HeadingOffset,
) -> impl fmt::Display + 'a + Captures<'cx> {
if let Some(ref name) = item.name {
info!("Documenting {name}");
}
display_fn(move |f| {
document_item_info(cx, item, parent).render_into(f).unwrap();
if parent.is_none() {
write!(f, "{}", document_full_collapsible(item, cx, heading_offset))
} else {
write!(f, "{}", document_full(item, cx, heading_offset))
}
})
}
/// Render md_text as markdown.
fn render_markdown<'a, 'cx: 'a>(
cx: &'a mut Context<'cx>,
md_text: &'a str,
links: Vec<RenderedLink>,
heading_offset: HeadingOffset,
) -> impl fmt::Display + 'a + Captures<'cx> {
display_fn(move |f| {
write!(
f,
"<div class=\"docblock\">{}</div>",
Markdown {
content: md_text,
links: &links,
ids: &mut cx.id_map,
error_codes: cx.shared.codes,
edition: cx.shared.edition(),
playground: &cx.shared.playground,
heading_offset,
}
.into_string()
)
})
}
/// Writes a documentation block containing only the first paragraph of the documentation. If the
/// docs are longer, a "Read more" link is appended to the end.
fn document_short<'a, 'cx: 'a>(
item: &'a clean::Item,
cx: &'a mut Context<'cx>,
link: AssocItemLink<'a>,
parent: &'a clean::Item,
show_def_docs: bool,
) -> impl fmt::Display + 'a + Captures<'cx> {
display_fn(move |f| {
document_item_info(cx, item, Some(parent)).render_into(f).unwrap();
if !show_def_docs {
return Ok(());
}
let s = item.doc_value();
if !s.is_empty() {
let (mut summary_html, has_more_content) =
MarkdownSummaryLine(&s, &item.links(cx)).into_string_with_has_more_content();
if has_more_content {
let link = format!(" <a{}>Read more</a>", assoc_href_attr(item, link, cx));
if let Some(idx) = summary_html.rfind("</p>") {
summary_html.insert_str(idx, &link);
} else {
summary_html.push_str(&link);
}
}
write!(f, "<div class='docblock'>{summary_html}</div>")?;
}
Ok(())
})
}
fn document_full_collapsible<'a, 'cx: 'a>(
item: &'a clean::Item,
cx: &'a mut Context<'cx>,
heading_offset: HeadingOffset,
) -> impl fmt::Display + 'a + Captures<'cx> {
document_full_inner(item, cx, true, heading_offset)
}
fn document_full<'a, 'cx: 'a>(
item: &'a clean::Item,
cx: &'a mut Context<'cx>,
heading_offset: HeadingOffset,
) -> impl fmt::Display + 'a + Captures<'cx> {
document_full_inner(item, cx, false, heading_offset)
}
fn document_full_inner<'a, 'cx: 'a>(
item: &'a clean::Item,
cx: &'a mut Context<'cx>,
is_collapsible: bool,
heading_offset: HeadingOffset,
) -> impl fmt::Display + 'a + Captures<'cx> {
display_fn(move |f| {
if let Some(s) = item.opt_doc_value() {
debug!("Doc block: =====\n{s}\n=====");
if is_collapsible {
write!(
f,
"<details class=\"toggle top-doc\" open>\
<summary class=\"hideme\">\
<span>Expand description</span>\
</summary>{}</details>",
render_markdown(cx, &s, item.links(cx), heading_offset)
)?;
} else {
write!(f, "{}", render_markdown(cx, &s, item.links(cx), heading_offset))?;
}
}
let kind = match &item.kind {
clean::ItemKind::StrippedItem(box kind) | kind => kind,
};
if let clean::ItemKind::FunctionItem(..) | clean::ItemKind::MethodItem(..) = kind {
render_call_locations(f, cx, item);
}
Ok(())
})
}
#[derive(Template)]
#[template(path = "item_info.html")]
struct ItemInfo {
items: Vec<ShortItemInfo>,
}
/// Add extra information about an item such as:
///
/// * Stability
/// * Deprecated
/// * Required features (through the `doc_cfg` feature)
fn document_item_info(
cx: &mut Context<'_>,
item: &clean::Item,
parent: Option<&clean::Item>,
) -> ItemInfo {
let items = short_item_info(item, cx, parent);
ItemInfo { items }
}
fn portability(item: &clean::Item, parent: Option<&clean::Item>) -> Option<String> {
let cfg = match (&item.cfg, parent.and_then(|p| p.cfg.as_ref())) {
(Some(cfg), Some(parent_cfg)) => cfg.simplify_with(parent_cfg),
(cfg, _) => cfg.as_deref().cloned(),
};
debug!(
"Portability {name:?} {item_cfg:?} (parent: {parent:?}) - {parent_cfg:?} = {cfg:?}",
name = item.name,
item_cfg = item.cfg,
parent_cfg = parent.and_then(|p| p.cfg.as_ref()),
);
Some(cfg?.render_long_html())
}
#[derive(Template)]
#[template(path = "short_item_info.html")]
enum ShortItemInfo {
/// A message describing the deprecation of this item
Deprecation {
message: String,
},
/// The feature corresponding to an unstable item, and optionally
/// a tracking issue URL and number.
Unstable {
feature: String,
tracking: Option<(String, u32)>,
},
Portability {
message: String,
},
}
/// Render the stability, deprecation and portability information that is displayed at the top of
/// the item's documentation.
fn short_item_info(
item: &clean::Item,
cx: &mut Context<'_>,
parent: Option<&clean::Item>,
) -> Vec<ShortItemInfo> {
let mut extra_info = vec![];
if let Some(depr @ Deprecation { note, since, suggestion: _ }) = item.deprecation(cx.tcx()) {
// We display deprecation messages for #[deprecated], but only display
// the future-deprecation messages for rustc versions.
let mut message = match since {
DeprecatedSince::RustcVersion(version) => {
if depr.is_in_effect() {
format!("Deprecated since {version}")
} else {
format!("Deprecating in {version}")
}
}
DeprecatedSince::Future => String::from("Deprecating in a future version"),
DeprecatedSince::NonStandard(since) => {
format!("Deprecated since {}", Escape(since.as_str()))
}
DeprecatedSince::Unspecified | DeprecatedSince::Err => String::from("Deprecated"),
};
if let Some(note) = note {
let note = note.as_str();
let html = MarkdownItemInfo(note, &mut cx.id_map);
message.push_str(": ");
message.push_str(&html.into_string());
}
extra_info.push(ShortItemInfo::Deprecation { message });
}
// Render unstable items. But don't render "rustc_private" crates (internal compiler crates).
// Those crates are permanently unstable so it makes no sense to render "unstable" everywhere.
if let Some((StabilityLevel::Unstable { reason: _, issue, .. }, feature)) = item
.stability(cx.tcx())
.as_ref()
.filter(|stab| stab.feature != sym::rustc_private)
.map(|stab| (stab.level, stab.feature))
{
let tracking = if let (Some(url), Some(issue)) = (&cx.shared.issue_tracker_base_url, issue)
{
Some((url.clone(), issue.get()))
} else {
None
};
extra_info.push(ShortItemInfo::Unstable { feature: feature.to_string(), tracking });
}
if let Some(message) = portability(item, parent) {
extra_info.push(ShortItemInfo::Portability { message });
}
extra_info
}
// Render the list of items inside one of the sections "Trait Implementations",
// "Auto Trait Implementations," "Blanket Trait Implementations" (on struct/enum pages).
pub(crate) fn render_impls(
cx: &mut Context<'_>,
mut w: impl Write,
impls: &[&Impl],
containing_item: &clean::Item,
toggle_open_by_default: bool,
) {
let tcx = cx.tcx();
let mut rendered_impls = impls
.iter()
.map(|i| {
let did = i.trait_did().unwrap();
let provided_trait_methods = i.inner_impl().provided_trait_methods(tcx);
let assoc_link = AssocItemLink::GotoSource(did.into(), &provided_trait_methods);
let mut buffer = Buffer::new();
render_impl(
&mut buffer,
cx,
i,
containing_item,
assoc_link,
RenderMode::Normal,
None,
&[],
ImplRenderingParameters {
show_def_docs: true,
show_default_items: true,
show_non_assoc_items: true,
toggle_open_by_default,
},
);
buffer.into_inner()
})
.collect::<Vec<_>>();
rendered_impls.sort();
w.write_str(&rendered_impls.join("")).unwrap();
}
/// Build a (possibly empty) `href` attribute (a key-value pair) for the given associated item.
fn assoc_href_attr(it: &clean::Item, link: AssocItemLink<'_>, cx: &Context<'_>) -> String {
let name = it.name.unwrap();
let item_type = it.type_();
let href = match link {
AssocItemLink::Anchor(Some(ref id)) => Some(format!("#{id}")),
AssocItemLink::Anchor(None) => Some(format!("#{item_type}.{name}")),
AssocItemLink::GotoSource(did, provided_methods) => {
// We're creating a link from the implementation of an associated item to its
// declaration in the trait declaration.
let item_type = match item_type {
// For historical but not technical reasons, the item type of methods in
// trait declarations depends on whether the method is required (`TyMethod`) or
// provided (`Method`).
ItemType::Method | ItemType::TyMethod => {
if provided_methods.contains(&name) {
ItemType::Method
} else {
ItemType::TyMethod
}
}
// For associated types and constants, no such distinction exists.
item_type => item_type,
};
match href(did.expect_def_id(), cx) {
Ok((url, ..)) => Some(format!("{url}#{item_type}.{name}")),
// The link is broken since it points to an external crate that wasn't documented.
// Do not create any link in such case. This is better than falling back to a
// dummy anchor like `#{item_type}.{name}` representing the `id` of *this* impl item
// (that used to happen in older versions). Indeed, in most cases this dummy would
// coincide with the `id`. However, it would not always do so.
// In general, this dummy would be incorrect:
// If the type with the trait impl also had an inherent impl with an assoc. item of
// the *same* name as this impl item, the dummy would link to that one even though
// those two items are distinct!
// In this scenario, the actual `id` of this impl item would be
// `#{item_type}.{name}-{n}` for some number `n` (a disambiguator).
Err(HrefError::DocumentationNotBuilt) => None,
Err(_) => Some(format!("#{item_type}.{name}")),
}
}
};
// If there is no `href` for the reason explained above, simply do not render it which is valid:
// https://html.spec.whatwg.org/multipage/links.html#links-created-by-a-and-area-elements
href.map(|href| format!(" href=\"{href}\"")).unwrap_or_default()
}
fn assoc_const(
w: &mut Buffer,
it: &clean::Item,
generics: &clean::Generics,
ty: &clean::Type,
default: Option<&clean::ConstantKind>,
link: AssocItemLink<'_>,
indent: usize,
cx: &Context<'_>,
) {
let tcx = cx.tcx();
write!(
w,
"{indent}{vis}const <a{href} class=\"constant\">{name}</a>{generics}: {ty}",
indent = " ".repeat(indent),
vis = visibility_print_with_space(it, cx),
href = assoc_href_attr(it, link, cx),
name = it.name.as_ref().unwrap(),
generics = generics.print(cx),
ty = ty.print(cx),
);
if let Some(default) = default {
w.write_str(" = ");
// FIXME: `.value()` uses `clean::utils::format_integer_with_underscore_sep` under the
// hood which adds noisy underscores and a type suffix to number literals.
// This hurts readability in this context especially when more complex expressions
// are involved and it doesn't add much of value.
// Find a way to print constants here without all that jazz.
write!(w, "{}", Escape(&default.value(tcx).unwrap_or_else(|| default.expr(tcx))));
}
write!(w, "{}", print_where_clause(generics, cx, indent, Ending::NoNewline));
}
fn assoc_type(
w: &mut Buffer,
it: &clean::Item,
generics: &clean::Generics,
bounds: &[clean::GenericBound],
default: Option<&clean::Type>,
link: AssocItemLink<'_>,
indent: usize,
cx: &Context<'_>,
) {
write!(
w,
"{indent}{vis}type <a{href} class=\"associatedtype\">{name}</a>{generics}",
indent = " ".repeat(indent),
vis = visibility_print_with_space(it, cx),
href = assoc_href_attr(it, link, cx),
name = it.name.as_ref().unwrap(),
generics = generics.print(cx),
);
if !bounds.is_empty() {
write!(w, ": {}", print_generic_bounds(bounds, cx))
}
// Render the default before the where-clause which aligns with the new recommended style. See #89122.
if let Some(default) = default {
write!(w, " = {}", default.print(cx))
}
write!(w, "{}", print_where_clause(generics, cx, indent, Ending::NoNewline));
}
fn assoc_method(
w: &mut Buffer,
meth: &clean::Item,
g: &clean::Generics,
d: &clean::FnDecl,
link: AssocItemLink<'_>,
parent: ItemType,
cx: &mut Context<'_>,
render_mode: RenderMode,
) {
let tcx = cx.tcx();
let header = meth.fn_header(tcx).expect("Trying to get header from a non-function item");
let name = meth.name.as_ref().unwrap();
let vis = visibility_print_with_space(meth, cx).to_string();
let defaultness = print_default_space(meth.is_default());
// FIXME: Once https://github.com/rust-lang/rust/issues/67792 is implemented, we can remove
// this condition.
let constness = match render_mode {
RenderMode::Normal => print_constness_with_space(
&header.constness,
meth.stable_since(tcx),
meth.const_stability(tcx),
),
RenderMode::ForDeref { .. } => "",
};
let asyncness = header.asyncness.print_with_space();
let safety = header.safety.print_with_space();
let abi = print_abi_with_space(header.abi).to_string();
let href = assoc_href_attr(meth, link, cx);
// NOTE: `{:#}` does not print HTML formatting, `{}` does. So `g.print` can't be reused between the length calculation and `write!`.
let generics_len = format!("{:#}", g.print(cx)).len();
let mut header_len = "fn ".len()
+ vis.len()
+ defaultness.len()
+ constness.len()
+ asyncness.len()
+ safety.len()
+ abi.len()
+ name.as_str().len()
+ generics_len;
let notable_traits = notable_traits_button(&d.output, cx);
let (indent, indent_str, end_newline) = if parent == ItemType::Trait {
header_len += 4;
let indent_str = " ";
write!(w, "{}", render_attributes_in_pre(meth, indent_str, cx));
(4, indent_str, Ending::NoNewline)
} else {
render_attributes_in_code(w, meth, cx);
(0, "", Ending::Newline)
};
w.reserve(header_len + "<a href=\"\" class=\"fn\">{".len() + "</a>".len());
write!(
w,
"{indent}{vis}{defaultness}{constness}{asyncness}{safety}{abi}fn \
<a{href} class=\"fn\">{name}</a>{generics}{decl}{notable_traits}{where_clause}",
indent = indent_str,
vis = vis,
defaultness = defaultness,
constness = constness,
asyncness = asyncness,
safety = safety,
abi = abi,
href = href,
name = name,
generics = g.print(cx),
decl = d.full_print(header_len, indent, cx),
notable_traits = notable_traits.unwrap_or_default(),
where_clause = print_where_clause(g, cx, indent, end_newline),
);
}
/// Writes a span containing the versions at which an item became stable and/or const-stable. For
/// example, if the item became stable at 1.0.0, and const-stable at 1.45.0, this function would
/// write a span containing "1.0.0 (const: 1.45.0)".
///
/// Returns `true` if a stability annotation was rendered.
///
/// Stability and const-stability are considered separately. If the item is unstable, no version
/// will be written. If the item is const-unstable, "const: unstable" will be appended to the
/// span, with a link to the tracking issue if present. If an item's stability or const-stability
/// version matches the version of its enclosing item, that version will be omitted.
///
/// Note that it is possible for an unstable function to be const-stable. In that case, the span
/// will include the const-stable version, but no stable version will be emitted, as a natural
/// consequence of the above rules.
fn render_stability_since_raw_with_extra(
w: &mut Buffer,
stable_version: Option<StableSince>,
const_stability: Option<ConstStability>,
extra_class: &str,
) -> bool {
let mut title = String::new();
let mut stability = String::new();
if let Some(version) = stable_version.and_then(|version| since_to_string(&version)) {
stability.push_str(&version);
title.push_str(&format!("Stable since Rust version {version}"));
}
let const_title_and_stability = match const_stability {
Some(ConstStability { level: StabilityLevel::Stable { since, .. }, .. }) => {
since_to_string(&since)
.map(|since| (format!("const since {since}"), format!("const: {since}")))
}
Some(ConstStability { level: StabilityLevel::Unstable { issue, .. }, feature, .. }) => {
if stable_version.is_none() {
// don't display const unstable if entirely unstable
None
} else {
let unstable = if let Some(n) = issue {
format!(
"<a \
href=\"https://github.com/rust-lang/rust/issues/{n}\" \
title=\"Tracking issue for {feature}\"\
>unstable</a>"
)
} else {
String::from("unstable")
};
Some((String::from("const unstable"), format!("const: {unstable}")))
}
}
_ => None,
};
if let Some((const_title, const_stability)) = const_title_and_stability {
if !title.is_empty() {
title.push_str(&format!(", {const_title}"));
} else {
title.push_str(&const_title);
}
if !stability.is_empty() {
stability.push_str(&format!(" ({const_stability})"));
} else {
stability.push_str(&const_stability);
}
}
if !stability.is_empty() {
write!(w, r#"<span class="since{extra_class}" title="{title}">{stability}</span>"#);
}
!stability.is_empty()
}
fn since_to_string(since: &StableSince) -> Option<String> {
match since {
StableSince::Version(since) => Some(since.to_string()),
StableSince::Current => Some(RustcVersion::CURRENT.to_string()),
StableSince::Err => None,
}
}
#[inline]
fn render_stability_since_raw(
w: &mut Buffer,
ver: Option<StableSince>,
const_stability: Option<ConstStability>,
) -> bool {
render_stability_since_raw_with_extra(w, ver, const_stability, "")
}
fn render_assoc_item(
w: &mut Buffer,
item: &clean::Item,
link: AssocItemLink<'_>,
parent: ItemType,
cx: &mut Context<'_>,
render_mode: RenderMode,
) {
match &item.kind {
clean::StrippedItem(..) => {}
clean::TyMethodItem(m) => {
assoc_method(w, item, &m.generics, &m.decl, link, parent, cx, render_mode)
}
clean::MethodItem(m, _) => {
assoc_method(w, item, &m.generics, &m.decl, link, parent, cx, render_mode)
}
clean::TyAssocConstItem(generics, ty) => assoc_const(
w,
item,
generics,
ty,
None,
link,
if parent == ItemType::Trait { 4 } else { 0 },
cx,
),
clean::AssocConstItem(ci) => assoc_const(
w,
item,
&ci.generics,
&ci.type_,
Some(&ci.kind),
link,
if parent == ItemType::Trait { 4 } else { 0 },
cx,
),
clean::TyAssocTypeItem(ref generics, ref bounds) => assoc_type(
w,
item,
generics,
bounds,
None,
link,
if parent == ItemType::Trait { 4 } else { 0 },
cx,
),
clean::AssocTypeItem(ref ty, ref bounds) => assoc_type(
w,
item,
&ty.generics,
bounds,
Some(ty.item_type.as_ref().unwrap_or(&ty.type_)),
link,
if parent == ItemType::Trait { 4 } else { 0 },
cx,
),
_ => panic!("render_assoc_item called on non-associated-item"),
}
}
// When an attribute is rendered inside a `<pre>` tag, it is formatted using
// a whitespace prefix and newline.
fn render_attributes_in_pre<'a, 'tcx: 'a>(
it: &'a clean::Item,
prefix: &'a str,
cx: &'a Context<'tcx>,
) -> impl fmt::Display + Captures<'a> + Captures<'tcx> {
crate::html::format::display_fn(move |f| {
for a in it.attributes(cx.tcx(), cx.cache(), false) {
writeln!(f, "{prefix}{a}")?;
}
Ok(())
})
}
// When an attribute is rendered inside a <code> tag, it is formatted using
// a div to produce a newline after it.
fn render_attributes_in_code(w: &mut impl fmt::Write, it: &clean::Item, cx: &Context<'_>) {
for attr in it.attributes(cx.tcx(), cx.cache(), false) {
write!(w, "<div class=\"code-attribute\">{attr}</div>").unwrap();
}
}
#[derive(Copy, Clone)]
enum AssocItemLink<'a> {
Anchor(Option<&'a str>),
GotoSource(ItemId, &'a FxIndexSet<Symbol>),
}
impl<'a> AssocItemLink<'a> {
fn anchor(&self, id: &'a str) -> Self {
match *self {
AssocItemLink::Anchor(_) => AssocItemLink::Anchor(Some(id)),
ref other => *other,
}
}
}
pub fn write_section_heading(
w: &mut impl fmt::Write,
title: &str,
id: &str,
extra_class: Option<&str>,
extra: impl fmt::Display,
) {
let (extra_class, whitespace) = match extra_class {
Some(extra) => (extra, " "),
None => ("", ""),
};
write!(
w,
"<h2 id=\"{id}\" class=\"{extra_class}{whitespace}section-header\">\
{title}\
<a href=\"#{id}\" class=\"anchor\">§</a>\
</h2>{extra}",
)
.unwrap();
}
fn write_impl_section_heading(w: &mut impl fmt::Write, title: &str, id: &str) {
write_section_heading(w, title, id, None, "")
}
pub(crate) fn render_all_impls(
mut w: impl Write,
cx: &mut Context<'_>,
containing_item: &clean::Item,
concrete: &[&Impl],
synthetic: &[&Impl],
blanket_impl: &[&Impl],
) {
let mut impls = Buffer::html();
render_impls(cx, &mut impls, concrete, containing_item, true);
let impls = impls.into_inner();
if !impls.is_empty() {
write_impl_section_heading(&mut w, "Trait Implementations", "trait-implementations");
write!(w, "<div id=\"trait-implementations-list\">{impls}</div>").unwrap();
}
if !synthetic.is_empty() {
write_impl_section_heading(
&mut w,
"Auto Trait Implementations",
"synthetic-implementations",
);
w.write_str("<div id=\"synthetic-implementations-list\">").unwrap();
render_impls(cx, &mut w, synthetic, containing_item, false);
w.write_str("</div>").unwrap();
}
if !blanket_impl.is_empty() {
write_impl_section_heading(&mut w, "Blanket Implementations", "blanket-implementations");
w.write_str("<div id=\"blanket-implementations-list\">").unwrap();
render_impls(cx, &mut w, blanket_impl, containing_item, false);
w.write_str("</div>").unwrap();
}
}
fn render_assoc_items<'a, 'cx: 'a>(
cx: &'a mut Context<'cx>,
containing_item: &'a clean::Item,
it: DefId,
what: AssocItemRender<'a>,
) -> impl fmt::Display + 'a + Captures<'cx> {
let mut derefs = DefIdSet::default();
derefs.insert(it);
display_fn(move |f| {
render_assoc_items_inner(f, cx, containing_item, it, what, &mut derefs);
Ok(())
})
}
fn render_assoc_items_inner(
mut w: &mut dyn fmt::Write,
cx: &mut Context<'_>,
containing_item: &clean::Item,
it: DefId,
what: AssocItemRender<'_>,
derefs: &mut DefIdSet,
) {
info!("Documenting associated items of {:?}", containing_item.name);
let shared = Rc::clone(&cx.shared);
let cache = &shared.cache;
let Some(v) = cache.impls.get(&it) else { return };
let (non_trait, traits): (Vec<_>, _) = v.iter().partition(|i| i.inner_impl().trait_.is_none());
if !non_trait.is_empty() {
let mut close_tags = <Vec<&str>>::with_capacity(1);
let mut tmp_buf = Buffer::html();
let (render_mode, id, class_html) = match what {
AssocItemRender::All => {
write_impl_section_heading(&mut tmp_buf, "Implementations", "implementations");
(RenderMode::Normal, "implementations-list".to_owned(), "")
}
AssocItemRender::DerefFor { trait_, type_, deref_mut_ } => {
let id =
cx.derive_id(small_url_encode(format!("deref-methods-{:#}", type_.print(cx))));
let derived_id = cx.derive_id(&id);
tmp_buf.write_str("<details class=\"toggle big-toggle\" open><summary>");
close_tags.push("</details>");
write_impl_section_heading(
&mut tmp_buf,
&format!(
"<span>Methods from {trait_}&lt;Target = {type_}&gt;</span>",
trait_ = trait_.print(cx),
type_ = type_.print(cx),
),
&id,
);
tmp_buf.write_str("</summary>");
if let Some(def_id) = type_.def_id(cx.cache()) {
cx.deref_id_map.insert(def_id, id);
}
(RenderMode::ForDeref { mut_: deref_mut_ }, derived_id, r#" class="impl-items""#)
}
};
let mut impls_buf = Buffer::html();
for i in &non_trait {
render_impl(
&mut impls_buf,
cx,
i,
containing_item,
AssocItemLink::Anchor(None),
render_mode,
None,
&[],
ImplRenderingParameters {
show_def_docs: true,
show_default_items: true,
show_non_assoc_items: true,
toggle_open_by_default: true,
},
);
}
if !impls_buf.is_empty() {
write!(
w,
"{}<div id=\"{id}\"{class_html}>{}</div>",
tmp_buf.into_inner(),
impls_buf.into_inner()
)
.unwrap();
for tag in close_tags.into_iter().rev() {
w.write_str(tag).unwrap();
}
}
}
if !traits.is_empty() {
let deref_impl =
traits.iter().find(|t| t.trait_did() == cx.tcx().lang_items().deref_trait());
if let Some(impl_) = deref_impl {
let has_deref_mut =
traits.iter().any(|t| t.trait_did() == cx.tcx().lang_items().deref_mut_trait());
render_deref_methods(&mut w, cx, impl_, containing_item, has_deref_mut, derefs);
}
// If we were already one level into rendering deref methods, we don't want to render
// anything after recursing into any further deref methods above.
if let AssocItemRender::DerefFor { .. } = what {
return;
}
let (synthetic, concrete): (Vec<&Impl>, Vec<&Impl>) =
traits.into_iter().partition(|t| t.inner_impl().kind.is_auto());
let (blanket_impl, concrete): (Vec<&Impl>, _) =
concrete.into_iter().partition(|t| t.inner_impl().kind.is_blanket());
render_all_impls(w, cx, containing_item, &concrete, &synthetic, &blanket_impl);
}
}
fn render_deref_methods(
mut w: impl Write,
cx: &mut Context<'_>,
impl_: &Impl,
container_item: &clean::Item,
deref_mut: bool,
derefs: &mut DefIdSet,
) {
let cache = cx.cache();
let deref_type = impl_.inner_impl().trait_.as_ref().unwrap();
let (target, real_target) = impl_
.inner_impl()
.items
.iter()
.find_map(|item| match item.kind {
clean::AssocTypeItem(box ref t, _) => Some(match *t {
clean::TypeAlias { item_type: Some(ref type_), .. } => (type_, &t.type_),
_ => (&t.type_, &t.type_),
}),
_ => None,
})
.expect("Expected associated type binding");
debug!(
"Render deref methods for {for_:#?}, target {target:#?}",
for_ = impl_.inner_impl().for_
);
let what =
AssocItemRender::DerefFor { trait_: deref_type, type_: real_target, deref_mut_: deref_mut };
if let Some(did) = target.def_id(cache) {
if let Some(type_did) = impl_.inner_impl().for_.def_id(cache) {
// `impl Deref<Target = S> for S`
if did == type_did || !derefs.insert(did) {
// Avoid infinite cycles
return;
}
}
render_assoc_items_inner(&mut w, cx, container_item, did, what, derefs);
} else if let Some(prim) = target.primitive_type() {
if let Some(&did) = cache.primitive_locations.get(&prim) {
render_assoc_items_inner(&mut w, cx, container_item, did, what, derefs);
}
}
}
fn should_render_item(item: &clean::Item, deref_mut_: bool, tcx: TyCtxt<'_>) -> bool {
let self_type_opt = match item.kind {
clean::MethodItem(ref method, _) => method.decl.receiver_type(),
clean::TyMethodItem(ref method) => method.decl.receiver_type(),
_ => None,
};
if let Some(self_ty) = self_type_opt {
let (by_mut_ref, by_box, by_value) = match *self_ty {
clean::Type::BorrowedRef { mutability, .. } => {
(mutability == Mutability::Mut, false, false)
}
clean::Type::Path { ref path } => {
(false, Some(path.def_id()) == tcx.lang_items().owned_box(), false)
}
clean::Type::SelfTy => (false, false, true),
_ => (false, false, false),
};
(deref_mut_ || !by_mut_ref) && !by_box && !by_value
} else {
false
}
}
pub(crate) fn notable_traits_button(ty: &clean::Type, cx: &mut Context<'_>) -> Option<String> {
let mut has_notable_trait = false;
if ty.is_unit() {
// Very common fast path.
return None;
}
let did = ty.def_id(cx.cache())?;
// Box has pass-through impls for Read, Write, Iterator, and Future when the
// boxed type implements one of those. We don't want to treat every Box return
// as being notably an Iterator (etc), though, so we exempt it. Pin has the same
// issue, with a pass-through impl for Future.
if Some(did) == cx.tcx().lang_items().owned_box()
|| Some(did) == cx.tcx().lang_items().pin_type()
{
return None;
}
if let Some(impls) = cx.cache().impls.get(&did) {
for i in impls {
let impl_ = i.inner_impl();
if impl_.polarity != ty::ImplPolarity::Positive {
continue;
}
if !ty.is_doc_subtype_of(&impl_.for_, cx.cache()) {
// Two different types might have the same did,
// without actually being the same.
continue;
}
if let Some(trait_) = &impl_.trait_ {
let trait_did = trait_.def_id();
if cx.cache().traits.get(&trait_did).is_some_and(|t| t.is_notable_trait(cx.tcx())) {
has_notable_trait = true;
}
}
}
}
if has_notable_trait {
cx.types_with_notable_traits.insert(ty.clone());
Some(format!(
" <a href=\"#\" class=\"tooltip\" data-notable-ty=\"{ty}\">ⓘ</a>",
ty = Escape(&format!("{:#}", ty.print(cx))),
))
} else {
None
}
}
fn notable_traits_decl(ty: &clean::Type, cx: &Context<'_>) -> (String, String) {
let mut out = Buffer::html();
let did = ty.def_id(cx.cache()).expect("notable_traits_button already checked this");
let impls = cx.cache().impls.get(&did).expect("notable_traits_button already checked this");
for i in impls {
let impl_ = i.inner_impl();
if impl_.polarity != ty::ImplPolarity::Positive {
continue;
}
if !ty.is_doc_subtype_of(&impl_.for_, cx.cache()) {
// Two different types might have the same did,
// without actually being the same.
continue;
}
if let Some(trait_) = &impl_.trait_ {
let trait_did = trait_.def_id();
if cx.cache().traits.get(&trait_did).is_some_and(|t| t.is_notable_trait(cx.tcx())) {
if out.is_empty() {
write!(
&mut out,
"<h3>Notable traits for <code>{}</code></h3>\
<pre><code>",
impl_.for_.print(cx)
);
}
write!(&mut out, "<div class=\"where\">{}</div>", impl_.print(false, cx));
for it in &impl_.items {
if let clean::AssocTypeItem(ref tydef, ref _bounds) = it.kind {
out.push_str("<div class=\"where\"> ");
let empty_set = FxIndexSet::default();
let src_link = AssocItemLink::GotoSource(trait_did.into(), &empty_set);
assoc_type(
&mut out,
it,
&tydef.generics,
&[], // intentionally leaving out bounds
Some(&tydef.type_),
src_link,
0,
cx,
);
out.push_str(";</div>");
}
}
}
}
}
if out.is_empty() {
out.write_str("</code></pre>");
}
(format!("{:#}", ty.print(cx)), out.into_inner())
}
pub(crate) fn notable_traits_json<'a>(
tys: impl Iterator<Item = &'a clean::Type>,
cx: &Context<'_>,
) -> String {
let mut mp: Vec<(String, String)> = tys.map(|ty| notable_traits_decl(ty, cx)).collect();
mp.sort_by(|(name1, _html1), (name2, _html2)| name1.cmp(name2));
struct NotableTraitsMap(Vec<(String, String)>);
impl Serialize for NotableTraitsMap {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
let mut map = serializer.serialize_map(Some(self.0.len()))?;
for item in &self.0 {
map.serialize_entry(&item.0, &item.1)?;
}
map.end()
}
}
serde_json::to_string(&NotableTraitsMap(mp))
.expect("serialize (string, string) -> json object cannot fail")
}
#[derive(Clone, Copy, Debug)]
struct ImplRenderingParameters {
show_def_docs: bool,
show_default_items: bool,
/// Whether or not to show methods.
show_non_assoc_items: bool,
toggle_open_by_default: bool,
}
fn render_impl(
w: &mut Buffer,
cx: &mut Context<'_>,
i: &Impl,
parent: &clean::Item,
link: AssocItemLink<'_>,
render_mode: RenderMode,
use_absolute: Option<bool>,
aliases: &[String],
rendering_params: ImplRenderingParameters,
) {
let shared = Rc::clone(&cx.shared);
let cache = &shared.cache;
let traits = &cache.traits;
let trait_ = i.trait_did().map(|did| &traits[&did]);
let mut close_tags = <Vec<&str>>::with_capacity(2);
// For trait implementations, the `interesting` output contains all methods that have doc
// comments, and the `boring` output contains all methods that do not. The distinction is
// used to allow hiding the boring methods.
// `containing_item` is used for rendering stability info. If the parent is a trait impl,
// `containing_item` will the grandparent, since trait impls can't have stability attached.
fn doc_impl_item(
boring: &mut Buffer,
interesting: &mut Buffer,
cx: &mut Context<'_>,
item: &clean::Item,
parent: &clean::Item,
link: AssocItemLink<'_>,
render_mode: RenderMode,
is_default_item: bool,
trait_: Option<&clean::Trait>,
rendering_params: ImplRenderingParameters,
) {
let item_type = item.type_();
let name = item.name.as_ref().unwrap();
let render_method_item = rendering_params.show_non_assoc_items
&& match render_mode {
RenderMode::Normal => true,
RenderMode::ForDeref { mut_: deref_mut_ } => {
should_render_item(item, deref_mut_, cx.tcx())
}
};
let in_trait_class = if trait_.is_some() { " trait-impl" } else { "" };
let mut doc_buffer = Buffer::empty_from(boring);
let mut info_buffer = Buffer::empty_from(boring);
let mut short_documented = true;
if render_method_item {
if !is_default_item {
if let Some(t) = trait_ {
// The trait item may have been stripped so we might not
// find any documentation or stability for it.
if let Some(it) = t.items.iter().find(|i| i.name == item.name) {
// We need the stability of the item from the trait
// because impls can't have a stability.
if !item.doc_value().is_empty() {
document_item_info(cx, it, Some(parent))
.render_into(&mut info_buffer)
.unwrap();
write!(
&mut doc_buffer,
"{}",
document_full(item, cx, HeadingOffset::H5)
);
short_documented = false;
} else {
// In case the item isn't documented,
// provide short documentation from the trait.
write!(
&mut doc_buffer,
"{}",
document_short(
it,
cx,
link,
parent,
rendering_params.show_def_docs,
)
);
}
}
} else {
document_item_info(cx, item, Some(parent))
.render_into(&mut info_buffer)
.unwrap();
if rendering_params.show_def_docs {
write!(&mut doc_buffer, "{}", document_full(item, cx, HeadingOffset::H5));
short_documented = false;
}
}
} else {
write!(
&mut doc_buffer,
"{}",
document_short(item, cx, link, parent, rendering_params.show_def_docs)
);
}
}
let w = if short_documented && trait_.is_some() { interesting } else { boring };
let toggled = !doc_buffer.is_empty();
if toggled {
let method_toggle_class = if item_type.is_method() { " method-toggle" } else { "" };
write!(w, "<details class=\"toggle{method_toggle_class}\" open><summary>");
}
match &item.kind {
clean::MethodItem(..) | clean::TyMethodItem(_) => {
// Only render when the method is not static or we allow static methods
if render_method_item {
let id = cx.derive_id(format!("{item_type}.{name}"));
let source_id = trait_
.and_then(|trait_| {
trait_
.items
.iter()
.find(|item| item.name.map(|n| n == *name).unwrap_or(false))
})
.map(|item| format!("{}.{name}", item.type_()));
write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
render_rightside(w, cx, item, render_mode);
if trait_.is_some() {
// Anchors are only used on trait impls.
write!(w, "<a href=\"#{id}\" class=\"anchor\">§</a>");
}
w.write_str("<h4 class=\"code-header\">");
render_assoc_item(
w,
item,
link.anchor(source_id.as_ref().unwrap_or(&id)),
ItemType::Impl,
cx,
render_mode,
);
w.write_str("</h4></section>");
}
}
clean::TyAssocConstItem(ref generics, ref ty) => {
let source_id = format!("{item_type}.{name}");
let id = cx.derive_id(&source_id);
write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
render_rightside(w, cx, item, render_mode);
if trait_.is_some() {
// Anchors are only used on trait impls.
write!(w, "<a href=\"#{id}\" class=\"anchor\">§</a>");
}
w.write_str("<h4 class=\"code-header\">");
assoc_const(
w,
item,
generics,
ty,
None,
link.anchor(if trait_.is_some() { &source_id } else { &id }),
0,
cx,
);
w.write_str("</h4></section>");
}
clean::AssocConstItem(ci) => {
let source_id = format!("{item_type}.{name}");
let id = cx.derive_id(&source_id);
write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
render_rightside(w, cx, item, render_mode);
if trait_.is_some() {
// Anchors are only used on trait impls.
write!(w, "<a href=\"#{id}\" class=\"anchor\">§</a>");
}
w.write_str("<h4 class=\"code-header\">");
assoc_const(
w,
item,
&ci.generics,
&ci.type_,
Some(&ci.kind),
link.anchor(if trait_.is_some() { &source_id } else { &id }),
0,
cx,
);
w.write_str("</h4></section>");
}
clean::TyAssocTypeItem(ref generics, ref bounds) => {
let source_id = format!("{item_type}.{name}");
let id = cx.derive_id(&source_id);
write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
render_rightside(w, cx, item, render_mode);
if trait_.is_some() {
// Anchors are only used on trait impls.
write!(w, "<a href=\"#{id}\" class=\"anchor\">§</a>");
}
w.write_str("<h4 class=\"code-header\">");
assoc_type(
w,
item,
generics,
bounds,
None,
link.anchor(if trait_.is_some() { &source_id } else { &id }),
0,
cx,
);
w.write_str("</h4></section>");
}
clean::AssocTypeItem(tydef, _bounds) => {
let source_id = format!("{item_type}.{name}");
let id = cx.derive_id(&source_id);
write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
render_rightside(w, cx, item, render_mode);
if trait_.is_some() {
// Anchors are only used on trait impls.
write!(w, "<a href=\"#{id}\" class=\"anchor\">§</a>");
}
w.write_str("<h4 class=\"code-header\">");
assoc_type(
w,
item,
&tydef.generics,
&[], // intentionally leaving out bounds
Some(tydef.item_type.as_ref().unwrap_or(&tydef.type_)),
link.anchor(if trait_.is_some() { &source_id } else { &id }),
0,
cx,
);
w.write_str("</h4></section>");
}
clean::StrippedItem(..) => return,
_ => panic!("can't make docs for trait item with name {:?}", item.name),
}
w.push_buffer(info_buffer);
if toggled {
w.write_str("</summary>");
w.push_buffer(doc_buffer);
w.push_str("</details>");
}
}
let mut impl_items = Buffer::empty_from(w);
let mut default_impl_items = Buffer::empty_from(w);
let impl_ = i.inner_impl();
// Impl items are grouped by kinds:
//
// 1. Constants
// 2. Types
// 3. Functions
//
// This order is because you can have associated constants used in associated types (like array
// length), and both in associcated functions. So with this order, when reading from top to
// bottom, you should see items definitions before they're actually used most of the time.
let mut assoc_types = Vec::new();
let mut methods = Vec::new();
if !impl_.is_negative_trait_impl() {
for trait_item in &impl_.items {
match trait_item.kind {
clean::MethodItem(..) | clean::TyMethodItem(_) => methods.push(trait_item),
clean::TyAssocTypeItem(..) | clean::AssocTypeItem(..) => {
assoc_types.push(trait_item)
}
clean::TyAssocConstItem(..) | clean::AssocConstItem(_) => {
// We render it directly since they're supposed to come first.
doc_impl_item(
&mut default_impl_items,
&mut impl_items,
cx,
trait_item,
if trait_.is_some() { &i.impl_item } else { parent },
link,
render_mode,
false,
trait_,
rendering_params,
);
}
_ => {}
}
}
for assoc_type in assoc_types {
doc_impl_item(
&mut default_impl_items,
&mut impl_items,
cx,
assoc_type,
if trait_.is_some() { &i.impl_item } else { parent },
link,
render_mode,
false,
trait_,
rendering_params,
);
}
for method in methods {
doc_impl_item(
&mut default_impl_items,
&mut impl_items,
cx,
method,
if trait_.is_some() { &i.impl_item } else { parent },
link,
render_mode,
false,
trait_,
rendering_params,
);
}
}
fn render_default_items(
boring: &mut Buffer,
interesting: &mut Buffer,
cx: &mut Context<'_>,
t: &clean::Trait,
i: &clean::Impl,
parent: &clean::Item,
render_mode: RenderMode,
rendering_params: ImplRenderingParameters,
) {
for trait_item in &t.items {
// Skip over any default trait items that are impossible to reference
// (e.g. if it has a `Self: Sized` bound on an unsized type).
if let Some(impl_def_id) = parent.item_id.as_def_id()
&& let Some(trait_item_def_id) = trait_item.item_id.as_def_id()
&& cx.tcx().is_impossible_associated_item((impl_def_id, trait_item_def_id))
{
continue;
}
let n = trait_item.name;
if i.items.iter().any(|m| m.name == n) {
continue;
}
let did = i.trait_.as_ref().unwrap().def_id();
let provided_methods = i.provided_trait_methods(cx.tcx());
let assoc_link = AssocItemLink::GotoSource(did.into(), &provided_methods);
doc_impl_item(
boring,
interesting,
cx,
trait_item,
parent,
assoc_link,
render_mode,
true,
Some(t),
rendering_params,
);
}
}
// If we've implemented a trait, then also emit documentation for all
// default items which weren't overridden in the implementation block.
// We don't emit documentation for default items if they appear in the
// Implementations on Foreign Types or Implementors sections.
if rendering_params.show_default_items {
if let Some(t) = trait_
&& !impl_.is_negative_trait_impl()
{
render_default_items(
&mut default_impl_items,
&mut impl_items,
cx,
t,
impl_,
&i.impl_item,
render_mode,
rendering_params,
);
}
}
if render_mode == RenderMode::Normal {
let toggled = !(impl_items.is_empty() && default_impl_items.is_empty());
if toggled {
close_tags.push("</details>");
write!(
w,
"<details class=\"toggle implementors-toggle\"{}>\
<summary>",
if rendering_params.toggle_open_by_default { " open" } else { "" }
);
}
render_impl_summary(
w,
cx,
i,
parent,
rendering_params.show_def_docs,
use_absolute,
aliases,
);
if toggled {
w.write_str("</summary>");
}
if let Some(ref dox) = i.impl_item.opt_doc_value() {
if trait_.is_none() && impl_.items.is_empty() {
w.write_str(
"<div class=\"item-info\">\
<div class=\"stab empty-impl\">This impl block contains no items.</div>\
</div>",
);
}
write!(
w,
"<div class=\"docblock\">{}</div>",
Markdown {
content: &*dox,
links: &i.impl_item.links(cx),
ids: &mut cx.id_map,
error_codes: cx.shared.codes,
edition: cx.shared.edition(),
playground: &cx.shared.playground,
heading_offset: HeadingOffset::H4,
}
.into_string()
);
}
if !default_impl_items.is_empty() || !impl_items.is_empty() {
w.write_str("<div class=\"impl-items\">");
close_tags.push("</div>");
}
}
if !default_impl_items.is_empty() || !impl_items.is_empty() {
w.push_buffer(default_impl_items);
w.push_buffer(impl_items);
}
for tag in close_tags.into_iter().rev() {
w.write_str(tag);
}
}
// Render the items that appear on the right side of methods, impls, and
// associated types. For example "1.0.0 (const: 1.39.0) · source".
fn render_rightside(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, render_mode: RenderMode) {
let tcx = cx.tcx();
// FIXME: Once https://github.com/rust-lang/rust/issues/67792 is implemented, we can remove
// this condition.
let const_stability = match render_mode {
RenderMode::Normal => item.const_stability(tcx),
RenderMode::ForDeref { .. } => None,
};
let src_href = cx.src_href(item);
let has_src_ref = src_href.is_some();
let mut rightside = Buffer::new();
let has_stability = render_stability_since_raw_with_extra(
&mut rightside,
item.stable_since(tcx),
const_stability,
if has_src_ref { "" } else { " rightside" },
);
if let Some(link) = src_href {
if has_stability {
write!(rightside, " · <a class=\"src\" href=\"{link}\">source</a>")
} else {
write!(rightside, "<a class=\"src rightside\" href=\"{link}\">source</a>")
}
}
if has_stability && has_src_ref {
write!(w, "<span class=\"rightside\">{}</span>", rightside.into_inner());
} else {
w.push_buffer(rightside);
}
}
pub(crate) fn render_impl_summary(
w: &mut Buffer,
cx: &mut Context<'_>,
i: &Impl,
parent: &clean::Item,
show_def_docs: bool,
use_absolute: Option<bool>,
// This argument is used to reference same type with different paths to avoid duplication
// in documentation pages for trait with automatic implementations like "Send" and "Sync".
aliases: &[String],
) {
let inner_impl = i.inner_impl();
let id = cx.derive_id(get_id_for_impl(cx.tcx(), i.impl_item.item_id));
let aliases = if aliases.is_empty() {
String::new()
} else {
format!(" data-aliases=\"{}\"", aliases.join(","))
};
write!(w, "<section id=\"{id}\" class=\"impl\"{aliases}>");
render_rightside(w, cx, &i.impl_item, RenderMode::Normal);
write!(
w,
"<a href=\"#{id}\" class=\"anchor\">§</a>\
<h3 class=\"code-header\">"
);
if let Some(use_absolute) = use_absolute {
write!(w, "{}", inner_impl.print(use_absolute, cx));
if show_def_docs {
for it in &inner_impl.items {
if let clean::AssocTypeItem(ref tydef, ref _bounds) = it.kind {
w.write_str("<div class=\"where\"> ");
assoc_type(
w,
it,
&tydef.generics,
&[], // intentionally leaving out bounds
Some(&tydef.type_),
AssocItemLink::Anchor(None),
0,
cx,
);
w.write_str(";</div>");
}
}
}
} else {
write!(w, "{}", inner_impl.print(false, cx));
}
w.write_str("</h3>");
let is_trait = inner_impl.trait_.is_some();
if is_trait && let Some(portability) = portability(&i.impl_item, Some(parent)) {
write!(
w,
"<span class=\"item-info\">\
<div class=\"stab portability\">{portability}</div>\
</span>",
);
}
w.write_str("</section>");
}
pub(crate) fn small_url_encode(s: String) -> String {
// These characters don't need to be escaped in a URI.
// See https://url.spec.whatwg.org/#query-percent-encode-set
// and https://url.spec.whatwg.org/#urlencoded-parsing
// and https://url.spec.whatwg.org/#url-code-points
fn dont_escape(c: u8) -> bool {
(b'a' <= c && c <= b'z')
|| (b'A' <= c && c <= b'Z')
|| (b'0' <= c && c <= b'9')
|| c == b'-'
|| c == b'_'
|| c == b'.'
|| c == b','
|| c == b'~'
|| c == b'!'
|| c == b'\''
|| c == b'('
|| c == b')'
|| c == b'*'
|| c == b'/'
|| c == b';'
|| c == b':'
|| c == b'?'
// As described in urlencoded-parsing, the
// first `=` is the one that separates key from
// value. Following `=`s are part of the value.
|| c == b'='
}
let mut st = String::new();
let mut last_match = 0;
for (idx, b) in s.bytes().enumerate() {
if dont_escape(b) {
continue;
}
if last_match != idx {
// Invariant: `idx` must be the first byte in a character at this point.
st += &s[last_match..idx];
}
if b == b' ' {
// URL queries are decoded with + replaced with SP.
// While the same is not true for hashes, rustdoc only needs to be
// consistent with itself when encoding them.
st += "+";
} else {
write!(st, "%{b:02X}").unwrap();
}
// Invariant: if the current byte is not at the start of a multi-byte character,
// we need to get down here so that when the next turn of the loop comes around,
// last_match winds up equalling idx.
//
// In other words, dont_escape must always return `false` in multi-byte character.
last_match = idx + 1;
}
if last_match != 0 {
st += &s[last_match..];
st
} else {
s
}
}
fn get_id_for_impl<'tcx>(tcx: TyCtxt<'tcx>, impl_id: ItemId) -> String {
use rustc_middle::ty::print::with_forced_trimmed_paths;
let (type_, trait_) = match impl_id {
ItemId::Auto { trait_, for_ } => {
let ty = tcx.type_of(for_).skip_binder();
(ty, Some(ty::TraitRef::new(tcx, trait_, [ty])))
}
ItemId::Blanket { impl_id, .. } | ItemId::DefId(impl_id) => {
match tcx.impl_subject(impl_id).skip_binder() {
ty::ImplSubject::Trait(trait_ref) => {
(trait_ref.args[0].expect_ty(), Some(trait_ref))
}
ty::ImplSubject::Inherent(ty) => (ty, None),
}
}
};
with_forced_trimmed_paths!(small_url_encode(if let Some(trait_) = trait_ {
format!("impl-{trait_}-for-{type_}", trait_ = trait_.print_only_trait_path())
} else {
format!("impl-{type_}")
}))
}
fn extract_for_impl_name(item: &clean::Item, cx: &Context<'_>) -> Option<(String, String)> {
match item.kind {
clean::ItemKind::ImplItem(ref i) if i.trait_.is_some() => {
// Alternative format produces no URLs,
// so this parameter does nothing.
Some((format!("{:#}", i.for_.print(cx)), get_id_for_impl(cx.tcx(), item.item_id)))
}
_ => None,
}
}
/// Returns the list of implementations for the primitive reference type, filtering out any
/// implementations that are on concrete or partially generic types, only keeping implementations
/// of the form `impl<T> Trait for &T`.
pub(crate) fn get_filtered_impls_for_reference<'a>(
shared: &'a Rc<SharedContext<'_>>,
it: &clean::Item,
) -> (Vec<&'a Impl>, Vec<&'a Impl>, Vec<&'a Impl>) {
let def_id = it.item_id.expect_def_id();
// If the reference primitive is somehow not defined, exit early.
let Some(v) = shared.cache.impls.get(&def_id) else {
return (Vec::new(), Vec::new(), Vec::new());
};
// Since there is no "direct implementation" on the reference primitive type, we filter out
// every implementation which isn't a trait implementation.
let traits = v.iter().filter(|i| i.inner_impl().trait_.is_some());
let (synthetic, concrete): (Vec<&Impl>, Vec<&Impl>) =
traits.partition(|t| t.inner_impl().kind.is_auto());
let (blanket_impl, concrete): (Vec<&Impl>, _) =
concrete.into_iter().partition(|t| t.inner_impl().kind.is_blanket());
// Now we keep only references over full generic types.
let concrete: Vec<_> = concrete
.into_iter()
.filter(|t| match t.inner_impl().for_ {
clean::Type::BorrowedRef { ref type_, .. } => type_.is_full_generic(),
_ => false,
})
.collect();
(concrete, synthetic, blanket_impl)
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub(crate) enum ItemSection {
Reexports,
PrimitiveTypes,
Modules,
Macros,
Structs,
Enums,
Constants,
Statics,
Traits,
Functions,
TypeAliases,
Unions,
Implementations,
TypeMethods,
Methods,
StructFields,
Variants,
AssociatedTypes,
AssociatedConstants,
ForeignTypes,
Keywords,
AttributeMacros,
DeriveMacros,
TraitAliases,
}
impl ItemSection {
const ALL: &'static [Self] = {
use ItemSection::*;
// NOTE: The order here affects the order in the UI.
// Keep this synchronized with addSidebarItems in main.js
&[
Reexports,
PrimitiveTypes,
Modules,
Macros,
Structs,
Enums,
Constants,
Statics,
Traits,
Functions,
TypeAliases,
Unions,
Implementations,
TypeMethods,
Methods,
StructFields,
Variants,
AssociatedTypes,
AssociatedConstants,
ForeignTypes,
Keywords,
AttributeMacros,
DeriveMacros,
TraitAliases,
]
};
fn id(self) -> &'static str {
match self {
Self::Reexports => "reexports",
Self::Modules => "modules",
Self::Structs => "structs",
Self::Unions => "unions",
Self::Enums => "enums",
Self::Functions => "functions",
Self::TypeAliases => "types",
Self::Statics => "statics",
Self::Constants => "constants",
Self::Traits => "traits",
Self::Implementations => "impls",
Self::TypeMethods => "tymethods",
Self::Methods => "methods",
Self::StructFields => "fields",
Self::Variants => "variants",
Self::Macros => "macros",
Self::PrimitiveTypes => "primitives",
Self::AssociatedTypes => "associated-types",
Self::AssociatedConstants => "associated-consts",
Self::ForeignTypes => "foreign-types",
Self::Keywords => "keywords",
Self::AttributeMacros => "attributes",
Self::DeriveMacros => "derives",
Self::TraitAliases => "trait-aliases",
}
}
fn name(self) -> &'static str {
match self {
Self::Reexports => "Re-exports",
Self::Modules => "Modules",
Self::Structs => "Structs",
Self::Unions => "Unions",
Self::Enums => "Enums",
Self::Functions => "Functions",
Self::TypeAliases => "Type Aliases",
Self::Statics => "Statics",
Self::Constants => "Constants",
Self::Traits => "Traits",
Self::Implementations => "Implementations",
Self::TypeMethods => "Type Methods",
Self::Methods => "Methods",
Self::StructFields => "Struct Fields",
Self::Variants => "Variants",
Self::Macros => "Macros",
Self::PrimitiveTypes => "Primitive Types",
Self::AssociatedTypes => "Associated Types",
Self::AssociatedConstants => "Associated Constants",
Self::ForeignTypes => "Foreign Types",
Self::Keywords => "Keywords",
Self::AttributeMacros => "Attribute Macros",
Self::DeriveMacros => "Derive Macros",
Self::TraitAliases => "Trait Aliases",
}
}
}
fn item_ty_to_section(ty: ItemType) -> ItemSection {
match ty {
ItemType::ExternCrate | ItemType::Import => ItemSection::Reexports,
ItemType::Module => ItemSection::Modules,
ItemType::Struct => ItemSection::Structs,
ItemType::Union => ItemSection::Unions,
ItemType::Enum => ItemSection::Enums,
ItemType::Function => ItemSection::Functions,
ItemType::TypeAlias => ItemSection::TypeAliases,
ItemType::Static => ItemSection::Statics,
ItemType::Constant => ItemSection::Constants,
ItemType::Trait => ItemSection::Traits,
ItemType::Impl => ItemSection::Implementations,
ItemType::TyMethod => ItemSection::TypeMethods,
ItemType::Method => ItemSection::Methods,
ItemType::StructField => ItemSection::StructFields,
ItemType::Variant => ItemSection::Variants,
ItemType::Macro => ItemSection::Macros,
ItemType::Primitive => ItemSection::PrimitiveTypes,
ItemType::AssocType => ItemSection::AssociatedTypes,
ItemType::AssocConst => ItemSection::AssociatedConstants,
ItemType::ForeignType => ItemSection::ForeignTypes,
ItemType::Keyword => ItemSection::Keywords,
ItemType::ProcAttribute => ItemSection::AttributeMacros,
ItemType::ProcDerive => ItemSection::DeriveMacros,
ItemType::TraitAlias => ItemSection::TraitAliases,
}
}
/// Returns a list of all paths used in the type.
/// This is used to help deduplicate imported impls
/// for reexported types. If any of the contained
/// types are re-exported, we don't use the corresponding
/// entry from the js file, as inlining will have already
/// picked up the impl
fn collect_paths_for_type(first_ty: clean::Type, cache: &Cache) -> Vec<String> {
let mut out = Vec::new();
let mut visited = FxHashSet::default();
let mut work = VecDeque::new();
let mut process_path = |did: DefId| {
let get_extern = || cache.external_paths.get(&did).map(|s| &s.0);
let fqp = cache.exact_paths.get(&did).or_else(get_extern);
if let Some(path) = fqp {
out.push(join_with_double_colon(&path));
}
};
work.push_back(first_ty);
while let Some(ty) = work.pop_front() {
if !visited.insert(ty.clone()) {
continue;
}
match ty {
clean::Type::Path { path } => process_path(path.def_id()),
clean::Type::Tuple(tys) => {
work.extend(tys.into_iter());
}
clean::Type::Slice(ty) => {
work.push_back(*ty);
}
clean::Type::Array(ty, _) => {
work.push_back(*ty);
}
clean::Type::RawPointer(_, ty) => {
work.push_back(*ty);
}
clean::Type::BorrowedRef { type_, .. } => {
work.push_back(*type_);
}
clean::Type::QPath(box clean::QPathData { self_type, trait_, .. }) => {
work.push_back(self_type);
if let Some(trait_) = trait_ {
process_path(trait_.def_id());
}
}
_ => {}
}
}
out
}
const MAX_FULL_EXAMPLES: usize = 5;
const NUM_VISIBLE_LINES: usize = 10;
/// Generates the HTML for example call locations generated via the --scrape-examples flag.
fn render_call_locations<W: fmt::Write>(mut w: W, cx: &mut Context<'_>, item: &clean::Item) {
let tcx = cx.tcx();
let def_id = item.item_id.expect_def_id();
let key = tcx.def_path_hash(def_id);
let Some(call_locations) = cx.shared.call_locations.get(&key) else { return };
// Generate a unique ID so users can link to this section for a given method
let id = cx.id_map.derive("scraped-examples");
write!(
&mut w,
"<div class=\"docblock scraped-example-list\">\
<span></span>\
<h5 id=\"{id}\">\
<a href=\"#{id}\">Examples found in repository</a>\
<a class=\"scrape-help\" href=\"{root_path}scrape-examples-help.html\">?</a>\
</h5>",
root_path = cx.root_path(),
id = id
)
.unwrap();
// Create a URL to a particular location in a reverse-dependency's source file
let link_to_loc = |call_data: &CallData, loc: &CallLocation| -> (String, String) {
let (line_lo, line_hi) = loc.call_expr.line_span;
let (anchor, title) = if line_lo == line_hi {
((line_lo + 1).to_string(), format!("line {}", line_lo + 1))
} else {
(
format!("{}-{}", line_lo + 1, line_hi + 1),
format!("lines {}-{}", line_lo + 1, line_hi + 1),
)
};
let url = format!("{}{}#{anchor}", cx.root_path(), call_data.url);
(url, title)
};
// Generate the HTML for a single example, being the title and code block
let write_example = |mut w: &mut W, (path, call_data): (&PathBuf, &CallData)| -> bool {
let contents = match fs::read_to_string(&path) {
Ok(contents) => contents,
Err(err) => {
let span = item.span(tcx).map_or(DUMMY_SP, |span| span.inner());
tcx.dcx().span_err(span, format!("failed to read file {}: {err}", path.display()));
return false;
}
};
// To reduce file sizes, we only want to embed the source code needed to understand the example, not
// the entire file. So we find the smallest byte range that covers all items enclosing examples.
assert!(!call_data.locations.is_empty());
let min_loc =
call_data.locations.iter().min_by_key(|loc| loc.enclosing_item.byte_span.0).unwrap();
let byte_min = min_loc.enclosing_item.byte_span.0;
let line_min = min_loc.enclosing_item.line_span.0;
let max_loc =
call_data.locations.iter().max_by_key(|loc| loc.enclosing_item.byte_span.1).unwrap();
let byte_max = max_loc.enclosing_item.byte_span.1;
let line_max = max_loc.enclosing_item.line_span.1;
// The output code is limited to that byte range.
let contents_subset = &contents[(byte_min as usize)..(byte_max as usize)];
// The call locations need to be updated to reflect that the size of the program has changed.
// Specifically, the ranges are all subtracted by `byte_min` since that's the new zero point.
let (mut byte_ranges, line_ranges): (Vec<_>, Vec<_>) = call_data
.locations
.iter()
.map(|loc| {
let (byte_lo, byte_hi) = loc.call_ident.byte_span;
let (line_lo, line_hi) = loc.call_expr.line_span;
let byte_range = (byte_lo - byte_min, byte_hi - byte_min);
let line_range = (line_lo - line_min, line_hi - line_min);
let (line_url, line_title) = link_to_loc(call_data, loc);
(byte_range, (line_range, line_url, line_title))
})
.unzip();
let (_, init_url, init_title) = &line_ranges[0];
let needs_expansion = line_max - line_min > NUM_VISIBLE_LINES;
let locations_encoded = serde_json::to_string(&line_ranges).unwrap();
// Look for the example file in the source map if it exists, otherwise return a dummy span
let file_span = (|| {
let source_map = tcx.sess.source_map();
let crate_src = tcx.sess.local_crate_source_file()?.into_local_path()?;
let abs_crate_src = crate_src.canonicalize().ok()?;
let crate_root = abs_crate_src.parent()?.parent()?;
let rel_path = path.strip_prefix(crate_root).ok()?;
let files = source_map.files();
let file = files.iter().find(|file| match &file.name {
FileName::Real(RealFileName::LocalPath(other_path)) => rel_path == other_path,
_ => false,
})?;
Some(rustc_span::Span::with_root_ctxt(
file.start_pos + BytePos(byte_min),
file.start_pos + BytePos(byte_max),
))
})()
.unwrap_or(DUMMY_SP);
let mut decoration_info = FxIndexMap::default();
decoration_info.insert("highlight focus", vec![byte_ranges.remove(0)]);
decoration_info.insert("highlight", byte_ranges);
sources::print_src(
&mut w,
contents_subset,
file_span,
cx,
&cx.root_path(),
highlight::DecorationInfo(decoration_info),
sources::SourceContext::Embedded(sources::ScrapedInfo {
needs_expansion,
offset: line_min,
name: &call_data.display_name,
url: init_url,
title: init_title,
locations: locations_encoded,
}),
);
true
};
// The call locations are output in sequence, so that sequence needs to be determined.
// Ideally the most "relevant" examples would be shown first, but there's no general algorithm
// for determining relevance. We instead proxy relevance with the following heuristics:
// 1. Code written to be an example is better than code not written to be an example, e.g.
// a snippet from examples/foo.rs is better than src/lib.rs. We don't know the Cargo
// directory structure in Rustdoc, so we proxy this by prioritizing code that comes from
// a --crate-type bin.
// 2. Smaller examples are better than large examples. So we prioritize snippets that have
// the smallest number of lines in their enclosing item.
// 3. Finally we sort by the displayed file name, which is arbitrary but prevents the
// ordering of examples from randomly changing between Rustdoc invocations.
let ordered_locations = {
fn sort_criterion<'a>(
(_, call_data): &(&PathBuf, &'a CallData),
) -> (bool, u32, &'a String) {
// Use the first location because that's what the user will see initially
let (lo, hi) = call_data.locations[0].enclosing_item.byte_span;
(!call_data.is_bin, hi - lo, &call_data.display_name)
}
let mut locs = call_locations.iter().collect::<Vec<_>>();
locs.sort_by_key(sort_criterion);
locs
};
let mut it = ordered_locations.into_iter().peekable();
// An example may fail to write if its source can't be read for some reason, so this method
// continues iterating until a write succeeds
let write_and_skip_failure = |w: &mut W, it: &mut Peekable<_>| {
while let Some(example) = it.next() {
if write_example(&mut *w, example) {
break;
}
}
};
// Write just one example that's visible by default in the method's description.
write_and_skip_failure(&mut w, &mut it);
// Then add the remaining examples in a hidden section.
if it.peek().is_some() {
write!(
w,
"<details class=\"toggle more-examples-toggle\">\
<summary class=\"hideme\">\
<span>More examples</span>\
</summary>\
<div class=\"hide-more\">Hide additional examples</div>\
<div class=\"more-scraped-examples\">\
<div class=\"toggle-line\"><div class=\"toggle-line-inner\"></div></div>"
)
.unwrap();
// Only generate inline code for MAX_FULL_EXAMPLES number of examples. Otherwise we could
// make the page arbitrarily huge!
for _ in 0..MAX_FULL_EXAMPLES {
write_and_skip_failure(&mut w, &mut it);
}
// For the remaining examples, generate a <ul> containing links to the source files.
if it.peek().is_some() {
w.write_str(
r#"<div class="example-links">Additional examples can be found in:<br><ul>"#,
)
.unwrap();
it.for_each(|(_, call_data)| {
let (url, _) = link_to_loc(call_data, &call_data.locations[0]);
write!(
w,
r#"<li><a href="{url}">{name}</a></li>"#,
url = url,
name = call_data.display_name
)
.unwrap();
});
w.write_str("</ul></div>").unwrap();
}
w.write_str("</div></details>").unwrap();
}
w.write_str("</div>").unwrap();
}