rust/crates/ide/src/doc_links.rs
Laurențiu Nicola 47afa4a5fc Bump misc deps
2021-05-24 16:31:54 +03:00

670 lines
24 KiB
Rust

//! Extracts, resolves and rewrites links and intra-doc links in markdown documentation.
use std::{
convert::{TryFrom, TryInto},
iter::once,
};
use itertools::Itertools;
use pulldown_cmark::{BrokenLink, CowStr, Event, InlineStr, LinkType, Options, Parser, Tag};
use pulldown_cmark_to_cmark::{cmark_with_options, Options as CmarkOptions};
use url::Url;
use hir::{
db::{DefDatabase, HirDatabase},
Adt, AsAssocItem, AssocItem, AssocItemContainer, Crate, Field, HasAttrs, ItemInNs, ModuleDef,
};
use ide_db::{
defs::{Definition, NameClass, NameRefClass},
RootDatabase,
};
use syntax::{
ast, match_ast, AstNode, SyntaxKind::*, SyntaxNode, SyntaxToken, TextRange, TokenAtOffset, T,
};
use crate::{FilePosition, Semantics};
pub(crate) type DocumentationLink = String;
/// Rewrite documentation links in markdown to point to an online host (e.g. docs.rs)
pub(crate) fn rewrite_links(db: &RootDatabase, markdown: &str, definition: &Definition) -> String {
let mut cb = broken_link_clone_cb;
let doc =
Parser::new_with_broken_link_callback(markdown, Options::ENABLE_TASKLISTS, Some(&mut cb));
let doc = map_links(doc, |target, title: &str| {
// This check is imperfect, there's some overlap between valid intra-doc links
// and valid URLs so we choose to be too eager to try to resolve what might be
// a URL.
if target.contains("://") {
(target.to_string(), title.to_string())
} else {
// Two possibilities:
// * path-based links: `../../module/struct.MyStruct.html`
// * module-based links (AKA intra-doc links): `super::super::module::MyStruct`
if let Some(rewritten) = rewrite_intra_doc_link(db, *definition, target, title) {
return rewritten;
}
if let Definition::ModuleDef(def) = *definition {
if let Some(target) = rewrite_url_link(db, def, target) {
return (target, title.to_string());
}
}
(target.to_string(), title.to_string())
}
});
let mut out = String::new();
let mut options = CmarkOptions::default();
options.code_block_backticks = 3;
cmark_with_options(doc, &mut out, None, options).ok();
out
}
/// Remove all links in markdown documentation.
pub(crate) fn remove_links(markdown: &str) -> String {
let mut drop_link = false;
let opts = Options::ENABLE_TASKLISTS | Options::ENABLE_FOOTNOTES;
let mut cb = |_: BrokenLink| {
let empty = InlineStr::try_from("").unwrap();
Some((CowStr::Inlined(empty), CowStr::Inlined(empty)))
};
let doc = Parser::new_with_broken_link_callback(markdown, opts, Some(&mut cb));
let doc = doc.filter_map(move |evt| match evt {
Event::Start(Tag::Link(link_type, ref target, ref title)) => {
if link_type == LinkType::Inline && target.contains("://") {
Some(Event::Start(Tag::Link(link_type, target.clone(), title.clone())))
} else {
drop_link = true;
None
}
}
Event::End(_) if drop_link => {
drop_link = false;
None
}
_ => Some(evt),
});
let mut out = String::new();
let mut options = CmarkOptions::default();
options.code_block_backticks = 3;
cmark_with_options(doc, &mut out, None, options).ok();
out
}
/// Retrieve a link to documentation for the given symbol.
pub(crate) fn external_docs(
db: &RootDatabase,
position: &FilePosition,
) -> Option<DocumentationLink> {
let sema = Semantics::new(db);
let file = sema.parse(position.file_id).syntax().clone();
let token = pick_best(file.token_at_offset(position.offset))?;
let token = sema.descend_into_macros(token);
let node = token.parent()?;
let definition = match_ast! {
match node {
ast::NameRef(name_ref) => NameRefClass::classify(&sema, &name_ref).map(|d| d.referenced(sema.db))?,
ast::Name(name) => NameClass::classify(&sema, &name).map(|d| d.referenced_or_defined(sema.db))?,
_ => return None,
}
};
get_doc_link(db, definition)
}
/// Extracts all links from a given markdown text.
pub(crate) fn extract_definitions_from_markdown(
markdown: &str,
) -> Vec<(TextRange, String, Option<hir::Namespace>)> {
Parser::new_with_broken_link_callback(
markdown,
Options::ENABLE_TASKLISTS,
Some(&mut broken_link_clone_cb),
)
.into_offset_iter()
.filter_map(|(event, range)| {
if let Event::Start(Tag::Link(_, target, title)) = event {
let link = if target.is_empty() { title } else { target };
let (link, ns) = parse_intra_doc_link(&link);
Some((
TextRange::new(range.start.try_into().ok()?, range.end.try_into().ok()?),
link.to_string(),
ns,
))
} else {
None
}
})
.collect()
}
pub(crate) fn resolve_doc_path_for_def(
db: &dyn HirDatabase,
def: Definition,
link: &str,
ns: Option<hir::Namespace>,
) -> Option<hir::ModuleDef> {
match def {
Definition::ModuleDef(def) => match def {
hir::ModuleDef::Module(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::Function(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::Adt(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::Variant(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::Const(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::Static(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::Trait(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::TypeAlias(it) => it.resolve_doc_path(db, &link, ns),
hir::ModuleDef::BuiltinType(_) => None,
},
Definition::Macro(it) => it.resolve_doc_path(db, &link, ns),
Definition::Field(it) => it.resolve_doc_path(db, &link, ns),
Definition::SelfType(_)
| Definition::Local(_)
| Definition::GenericParam(_)
| Definition::Label(_) => None,
}
}
pub(crate) fn doc_attributes(
sema: &Semantics<RootDatabase>,
node: &SyntaxNode,
) -> Option<(hir::AttrsWithOwner, Definition)> {
match_ast! {
match node {
ast::SourceFile(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Module(def)))),
ast::Module(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Module(def)))),
ast::Fn(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Function(def)))),
ast::Struct(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Adt(hir::Adt::Struct(def))))),
ast::Union(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Adt(hir::Adt::Union(def))))),
ast::Enum(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Adt(hir::Adt::Enum(def))))),
ast::Variant(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Variant(def)))),
ast::Trait(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Trait(def)))),
ast::Static(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Static(def)))),
ast::Const(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::Const(def)))),
ast::TypeAlias(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::ModuleDef(hir::ModuleDef::TypeAlias(def)))),
ast::Impl(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::SelfType(def))),
ast::RecordField(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
ast::TupleField(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
ast::Macro(it) => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Macro(def))),
// ast::Use(it) => sema.to_def(&it).map(|def| (Box::new(it) as _, def.attrs(sema.db))),
_ => return None
}
}
}
fn broken_link_clone_cb<'a, 'b>(link: BrokenLink<'a>) -> Option<(CowStr<'b>, CowStr<'b>)> {
// These allocations are actually unnecessary but the lifetimes on BrokenLinkCallback are wrong
// this is fixed in the repo but not on the crates.io release yet
Some((
/*url*/ link.reference.to_owned().into(),
/*title*/ link.reference.to_owned().into(),
))
}
// FIXME:
// BUG: For Option::Some
// Returns https://doc.rust-lang.org/nightly/core/prelude/v1/enum.Option.html#variant.Some
// Instead of https://doc.rust-lang.org/nightly/core/option/enum.Option.html
//
// This should cease to be a problem if RFC2988 (Stable Rustdoc URLs) is implemented
// https://github.com/rust-lang/rfcs/pull/2988
fn get_doc_link(db: &RootDatabase, definition: Definition) -> Option<String> {
// Get the outermost definition for the module def. This is used to resolve the public path to the type,
// then we can join the method, field, etc onto it if required.
let target_def: ModuleDef = match definition {
Definition::ModuleDef(def) => match def {
ModuleDef::Function(f) => f
.as_assoc_item(db)
.and_then(|assoc| match assoc.container(db) {
AssocItemContainer::Trait(t) => Some(t.into()),
AssocItemContainer::Impl(impl_) => {
impl_.self_ty(db).as_adt().map(|adt| adt.into())
}
})
.unwrap_or_else(|| def),
def => def,
},
Definition::Field(f) => f.parent_def(db).into(),
// FIXME: Handle macros
_ => return None,
};
let ns = ItemInNs::from(target_def);
let krate = match definition {
// Definition::module gives back the parent module, we don't want that as it fails for root modules
Definition::ModuleDef(ModuleDef::Module(module)) => module.krate(),
_ => definition.module(db)?.krate(),
};
let import_map = db.import_map(krate.into());
let mut base = krate.display_name(db)?.to_string();
let is_root_module = matches!(
definition,
Definition::ModuleDef(ModuleDef::Module(module)) if krate.root_module(db) == module
);
if !is_root_module {
base = once(base)
.chain(import_map.path_of(ns)?.segments.iter().map(|name| name.to_string()))
.join("/");
}
base += "/";
let filename = get_symbol_filename(db, &target_def);
let fragment = match definition {
Definition::ModuleDef(def) => match def {
ModuleDef::Function(f) => {
get_symbol_fragment(db, &FieldOrAssocItem::AssocItem(AssocItem::Function(f)))
}
ModuleDef::Const(c) => {
get_symbol_fragment(db, &FieldOrAssocItem::AssocItem(AssocItem::Const(c)))
}
ModuleDef::TypeAlias(ty) => {
get_symbol_fragment(db, &FieldOrAssocItem::AssocItem(AssocItem::TypeAlias(ty)))
}
_ => None,
},
Definition::Field(field) => get_symbol_fragment(db, &FieldOrAssocItem::Field(field)),
_ => None,
};
get_doc_url(db, &krate)?
.join(&base)
.ok()
.and_then(|mut url| {
if !matches!(definition, Definition::ModuleDef(ModuleDef::Module(..))) {
url.path_segments_mut().ok()?.pop();
};
Some(url)
})
.and_then(|url| url.join(filename.as_deref()?).ok())
.and_then(
|url| if let Some(fragment) = fragment { url.join(&fragment).ok() } else { Some(url) },
)
.map(|url| url.into())
}
fn rewrite_intra_doc_link(
db: &RootDatabase,
def: Definition,
target: &str,
title: &str,
) -> Option<(String, String)> {
let link = if target.is_empty() { title } else { target };
let (link, ns) = parse_intra_doc_link(link);
let resolved = resolve_doc_path_for_def(db, def, link, ns)?;
let krate = resolved.module(db)?.krate();
let canonical_path = resolved.canonical_path(db)?;
let mut new_url = get_doc_url(db, &krate)?
.join(&format!("{}/", krate.display_name(db)?))
.ok()?
.join(&canonical_path.replace("::", "/"))
.ok()?
.join(&get_symbol_filename(db, &resolved)?)
.ok()?;
if let ModuleDef::Trait(t) = resolved {
if let Some(assoc_item) = t.items(db).into_iter().find_map(|assoc_item| {
if let Some(name) = assoc_item.name(db) {
if *link == format!("{}::{}", canonical_path, name) {
return Some(assoc_item);
}
}
None
}) {
if let Some(fragment) =
get_symbol_fragment(db, &FieldOrAssocItem::AssocItem(assoc_item))
{
new_url = new_url.join(&fragment).ok()?;
}
};
}
Some((new_url.into(), strip_prefixes_suffixes(title).to_string()))
}
/// Try to resolve path to local documentation via path-based links (i.e. `../gateway/struct.Shard.html`).
fn rewrite_url_link(db: &RootDatabase, def: ModuleDef, target: &str) -> Option<String> {
if !(target.contains('#') || target.contains(".html")) {
return None;
}
let module = def.module(db)?;
let krate = module.krate();
let canonical_path = def.canonical_path(db)?;
let base = format!("{}/{}", krate.display_name(db)?, canonical_path.replace("::", "/"));
get_doc_url(db, &krate)
.and_then(|url| url.join(&base).ok())
.and_then(|url| {
get_symbol_filename(db, &def).as_deref().map(|f| url.join(f).ok()).flatten()
})
.and_then(|url| url.join(target).ok())
.map(|url| url.into())
}
/// Rewrites a markdown document, applying 'callback' to each link.
fn map_links<'e>(
events: impl Iterator<Item = Event<'e>>,
callback: impl Fn(&str, &str) -> (String, String),
) -> impl Iterator<Item = Event<'e>> {
let mut in_link = false;
let mut link_target: Option<CowStr> = None;
events.map(move |evt| match evt {
Event::Start(Tag::Link(_link_type, ref target, _)) => {
in_link = true;
link_target = Some(target.clone());
evt
}
Event::End(Tag::Link(link_type, _target, _)) => {
in_link = false;
Event::End(Tag::Link(link_type, link_target.take().unwrap(), CowStr::Borrowed("")))
}
Event::Text(s) if in_link => {
let (link_target_s, link_name) = callback(&link_target.take().unwrap(), &s);
link_target = Some(CowStr::Boxed(link_target_s.into()));
Event::Text(CowStr::Boxed(link_name.into()))
}
Event::Code(s) if in_link => {
let (link_target_s, link_name) = callback(&link_target.take().unwrap(), &s);
link_target = Some(CowStr::Boxed(link_target_s.into()));
Event::Code(CowStr::Boxed(link_name.into()))
}
_ => evt,
})
}
const TYPES: ([&str; 9], [&str; 0]) =
(["type", "struct", "enum", "mod", "trait", "union", "module", "prim", "primitive"], []);
const VALUES: ([&str; 8], [&str; 1]) =
(["value", "function", "fn", "method", "const", "static", "mod", "module"], ["()"]);
const MACROS: ([&str; 2], [&str; 1]) = (["macro", "derive"], ["!"]);
/// Extract the specified namespace from an intra-doc-link if one exists.
///
/// # Examples
///
/// * `struct MyStruct` -> ("MyStruct", `Namespace::Types`)
/// * `panic!` -> ("panic", `Namespace::Macros`)
/// * `fn@from_intra_spec` -> ("from_intra_spec", `Namespace::Values`)
fn parse_intra_doc_link(s: &str) -> (&str, Option<hir::Namespace>) {
let s = s.trim_matches('`');
[
(hir::Namespace::Types, (TYPES.0.iter(), TYPES.1.iter())),
(hir::Namespace::Values, (VALUES.0.iter(), VALUES.1.iter())),
(hir::Namespace::Macros, (MACROS.0.iter(), MACROS.1.iter())),
]
.iter()
.cloned()
.find_map(|(ns, (mut prefixes, mut suffixes))| {
if let Some(prefix) = prefixes.find(|&&prefix| {
s.starts_with(prefix)
&& s.chars().nth(prefix.len()).map_or(false, |c| c == '@' || c == ' ')
}) {
Some((&s[prefix.len() + 1..], ns))
} else {
suffixes.find_map(|&suffix| s.strip_suffix(suffix).zip(Some(ns)))
}
})
.map_or((s, None), |(s, ns)| (s, Some(ns)))
}
fn strip_prefixes_suffixes(s: &str) -> &str {
[
(TYPES.0.iter(), TYPES.1.iter()),
(VALUES.0.iter(), VALUES.1.iter()),
(MACROS.0.iter(), MACROS.1.iter()),
]
.iter()
.cloned()
.find_map(|(mut prefixes, mut suffixes)| {
if let Some(prefix) = prefixes.find(|&&prefix| {
s.starts_with(prefix)
&& s.chars().nth(prefix.len()).map_or(false, |c| c == '@' || c == ' ')
}) {
Some(&s[prefix.len() + 1..])
} else {
suffixes.find_map(|&suffix| s.strip_suffix(suffix))
}
})
.unwrap_or(s)
}
/// Get the root URL for the documentation of a crate.
///
/// ```
/// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
/// ^^^^^^^^^^^^^^^^^^^^^^^^^^
/// ```
fn get_doc_url(db: &RootDatabase, krate: &Crate) -> Option<Url> {
krate
.get_html_root_url(db)
.or_else(|| {
// Fallback to docs.rs. This uses `display_name` and can never be
// correct, but that's what fallbacks are about.
//
// FIXME: clicking on the link should just open the file in the editor,
// instead of falling back to external urls.
Some(format!("https://docs.rs/{}/*/", krate.display_name(db)?))
})
.and_then(|s| Url::parse(&s).ok())
}
/// Get the filename and extension generated for a symbol by rustdoc.
///
/// ```
/// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
/// ^^^^^^^^^^^^^^^^^^^
/// ```
fn get_symbol_filename(db: &dyn HirDatabase, definition: &ModuleDef) -> Option<String> {
Some(match definition {
ModuleDef::Adt(adt) => match adt {
Adt::Struct(s) => format!("struct.{}.html", s.name(db)),
Adt::Enum(e) => format!("enum.{}.html", e.name(db)),
Adt::Union(u) => format!("union.{}.html", u.name(db)),
},
ModuleDef::Module(_) => "index.html".to_string(),
ModuleDef::Trait(t) => format!("trait.{}.html", t.name(db)),
ModuleDef::TypeAlias(t) => format!("type.{}.html", t.name(db)),
ModuleDef::BuiltinType(t) => format!("primitive.{}.html", t.name()),
ModuleDef::Function(f) => format!("fn.{}.html", f.name(db)),
ModuleDef::Variant(ev) => {
format!("enum.{}.html#variant.{}", ev.parent_enum(db).name(db), ev.name(db))
}
ModuleDef::Const(c) => format!("const.{}.html", c.name(db)?),
ModuleDef::Static(s) => format!("static.{}.html", s.name(db)?),
})
}
enum FieldOrAssocItem {
Field(Field),
AssocItem(AssocItem),
}
/// Get the fragment required to link to a specific field, method, associated type, or associated constant.
///
/// ```
/// https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.next
/// ^^^^^^^^^^^^^^
/// ```
fn get_symbol_fragment(db: &dyn HirDatabase, field_or_assoc: &FieldOrAssocItem) -> Option<String> {
Some(match field_or_assoc {
FieldOrAssocItem::Field(field) => format!("#structfield.{}", field.name(db)),
FieldOrAssocItem::AssocItem(assoc) => match assoc {
AssocItem::Function(function) => {
let is_trait_method = function
.as_assoc_item(db)
.and_then(|assoc| assoc.containing_trait(db))
.is_some();
// This distinction may get more complicated when specialization is available.
// Rustdoc makes this decision based on whether a method 'has defaultness'.
// Currently this is only the case for provided trait methods.
if is_trait_method && !function.has_body(db) {
format!("#tymethod.{}", function.name(db))
} else {
format!("#method.{}", function.name(db))
}
}
AssocItem::Const(constant) => format!("#associatedconstant.{}", constant.name(db)?),
AssocItem::TypeAlias(ty) => format!("#associatedtype.{}", ty.name(db)),
},
})
}
fn pick_best(tokens: TokenAtOffset<SyntaxToken>) -> Option<SyntaxToken> {
return tokens.max_by_key(priority);
fn priority(n: &SyntaxToken) -> usize {
match n.kind() {
IDENT | INT_NUMBER => 3,
T!['('] | T![')'] => 2,
kind if kind.is_trivia() => 0,
_ => 1,
}
}
}
#[cfg(test)]
mod tests {
use expect_test::{expect, Expect};
use crate::fixture;
fn check(ra_fixture: &str, expect: Expect) {
let (analysis, position) = fixture::position(ra_fixture);
let url = analysis.external_docs(position).unwrap().expect("could not find url for symbol");
expect.assert_eq(&url)
}
#[test]
fn test_doc_url_crate() {
check(
r#"
//- /main.rs crate:main deps:test
use test$0::Foo;
//- /lib.rs crate:test
pub struct Foo;
"#,
expect![[r#"https://docs.rs/test/*/test/index.html"#]],
);
}
#[test]
fn test_doc_url_struct() {
check(
r#"
pub struct Fo$0o;
"#,
expect![[r#"https://docs.rs/test/*/test/struct.Foo.html"#]],
);
}
#[test]
fn test_doc_url_fn() {
check(
r#"
pub fn fo$0o() {}
"#,
expect![[r##"https://docs.rs/test/*/test/fn.foo.html#method.foo"##]],
);
}
#[test]
fn test_doc_url_inherent_method() {
check(
r#"
pub struct Foo;
impl Foo {
pub fn met$0hod() {}
}
"#,
expect![[r##"https://docs.rs/test/*/test/struct.Foo.html#method.method"##]],
);
}
#[test]
fn test_doc_url_trait_provided_method() {
check(
r#"
pub trait Bar {
fn met$0hod() {}
}
"#,
expect![[r##"https://docs.rs/test/*/test/trait.Bar.html#method.method"##]],
);
}
#[test]
fn test_doc_url_trait_required_method() {
check(
r#"
pub trait Foo {
fn met$0hod();
}
"#,
expect![[r##"https://docs.rs/test/*/test/trait.Foo.html#tymethod.method"##]],
);
}
#[test]
fn test_doc_url_field() {
check(
r#"
pub struct Foo {
pub fie$0ld: ()
}
"#,
expect![[r##"https://docs.rs/test/*/test/struct.Foo.html#structfield.field"##]],
);
}
#[test]
fn test_module() {
check(
r#"
pub mod foo {
pub mod ba$0r {}
}
"#,
expect![[r#"https://docs.rs/test/*/test/foo/bar/index.html"#]],
)
}
// FIXME: ImportMap will return re-export paths instead of public module
// paths. The correct path to documentation will never be a re-export.
// This problem stops us from resolving stdlib items included in the prelude
// such as `Option::Some` correctly.
#[ignore = "ImportMap may return re-exports"]
#[test]
fn test_reexport_order() {
check(
r#"
pub mod wrapper {
pub use module::Item;
pub mod module {
pub struct Item;
}
}
fn foo() {
let bar: wrapper::It$0em;
}
"#,
expect![[r#"https://docs.rs/test/*/test/wrapper/module/struct.Item.html"#]],
)
}
}