2021-07-15 16:27:01 +02:00

340 lines
12 KiB
Rust

//! Completion for attributes
//!
//! This module uses a bit of static metadata to provide completions
//! for built-in attributes.
use hir::HasAttrs;
use ide_db::helpers::generated_lints::{CLIPPY_LINTS, DEFAULT_LINTS, FEATURES};
use once_cell::sync::Lazy;
use rustc_hash::{FxHashMap, FxHashSet};
use syntax::{algo::non_trivia_sibling, ast, AstNode, Direction, NodeOrToken, SyntaxKind, T};
use crate::{
context::CompletionContext,
item::{CompletionItem, CompletionItemKind, CompletionKind},
Completions,
};
mod cfg;
mod derive;
mod lint;
mod repr;
pub(crate) fn complete_attribute(acc: &mut Completions, ctx: &CompletionContext) -> Option<()> {
let attribute = ctx.attribute_under_caret.as_ref()?;
match (attribute.path().and_then(|p| p.as_single_name_ref()), attribute.token_tree()) {
(Some(path), Some(token_tree)) => match path.text().as_str() {
"derive" => derive::complete_derive(acc, ctx, token_tree),
"repr" => repr::complete_repr(acc, ctx, token_tree),
"feature" => lint::complete_lint(acc, ctx, token_tree, FEATURES),
"allow" | "warn" | "deny" | "forbid" => {
lint::complete_lint(acc, ctx, token_tree.clone(), DEFAULT_LINTS);
lint::complete_lint(acc, ctx, token_tree, CLIPPY_LINTS);
}
"cfg" => {
cfg::complete_cfg(acc, ctx);
}
_ => (),
},
(None, Some(_)) => (),
_ => complete_new_attribute(acc, ctx, attribute),
}
Some(())
}
fn complete_new_attribute(acc: &mut Completions, ctx: &CompletionContext, attribute: &ast::Attr) {
let is_inner = attribute.kind() == ast::AttrKind::Inner;
let attribute_annotated_item_kind =
attribute.syntax().parent().map(|it| it.kind()).filter(|_| {
is_inner
// If we got nothing coming after the attribute it could be anything so filter it the kind out
|| non_trivia_sibling(attribute.syntax().clone().into(), Direction::Next).is_some()
});
let attributes = attribute_annotated_item_kind.and_then(|kind| {
if ast::Expr::can_cast(kind) {
Some(EXPR_ATTRIBUTES)
} else {
KIND_TO_ATTRIBUTES.get(&kind).copied()
}
});
let add_completion = |attr_completion: &AttrCompletion| {
let mut item = CompletionItem::new(
CompletionKind::Attribute,
ctx.source_range(),
attr_completion.label,
);
item.kind(CompletionItemKind::Attribute);
if let Some(lookup) = attr_completion.lookup {
item.lookup_by(lookup);
}
if let Some((snippet, cap)) = attr_completion.snippet.zip(ctx.config.snippet_cap) {
item.insert_snippet(cap, snippet);
}
if is_inner || !attr_completion.prefer_inner {
item.add_to(acc);
}
};
match attributes {
Some(applicable) => applicable
.iter()
.flat_map(|name| ATTRIBUTES.binary_search_by(|attr| attr.key().cmp(name)).ok())
.flat_map(|idx| ATTRIBUTES.get(idx))
.for_each(add_completion),
None if is_inner => ATTRIBUTES.iter().for_each(add_completion),
None => ATTRIBUTES.iter().filter(|compl| !compl.prefer_inner).for_each(add_completion),
}
// FIXME: write a test for this when we can
ctx.scope.process_all_names(&mut |name, scope_def| {
if let hir::ScopeDef::MacroDef(mac) = scope_def {
if mac.kind() == hir::MacroKind::Attr {
let mut item = CompletionItem::new(
CompletionKind::Attribute,
ctx.source_range(),
name.to_string(),
);
item.kind(CompletionItemKind::Attribute);
if let Some(docs) = mac.docs(ctx.sema.db) {
item.documentation(docs);
}
item.add_to(acc);
}
}
});
}
struct AttrCompletion {
label: &'static str,
lookup: Option<&'static str>,
snippet: Option<&'static str>,
prefer_inner: bool,
}
impl AttrCompletion {
fn key(&self) -> &'static str {
self.lookup.unwrap_or(self.label)
}
const fn prefer_inner(self) -> AttrCompletion {
AttrCompletion { prefer_inner: true, ..self }
}
}
const fn attr(
label: &'static str,
lookup: Option<&'static str>,
snippet: Option<&'static str>,
) -> AttrCompletion {
AttrCompletion { label, lookup, snippet, prefer_inner: false }
}
macro_rules! attrs {
// attributes applicable to all items
[@ { item $($tt:tt)* } {$($acc:tt)*}] => {
attrs!(@ { $($tt)* } { $($acc)*, "deprecated", "doc", "dochidden", "docalias", "must_use", "no_mangle" })
};
// attributes applicable to all adts
[@ { adt $($tt:tt)* } {$($acc:tt)*}] => {
attrs!(@ { $($tt)* } { $($acc)*, "derive", "repr" })
};
// attributes applicable to all linkable things aka functions/statics
[@ { linkable $($tt:tt)* } {$($acc:tt)*}] => {
attrs!(@ { $($tt)* } { $($acc)*, "export_name", "link_name", "link_section" })
};
// error fallback for nicer error message
[@ { $ty:ident $($tt:tt)* } {$($acc:tt)*}] => {
compile_error!(concat!("unknown attr subtype ", stringify!($ty)))
};
// general push down accumulation
[@ { $lit:literal $($tt:tt)*} {$($acc:tt)*}] => {
attrs!(@ { $($tt)* } { $($acc)*, $lit })
};
[@ {$($tt:tt)+} {$($tt2:tt)*}] => {
compile_error!(concat!("Unexpected input ", stringify!($($tt)+)))
};
// final output construction
[@ {} {$($tt:tt)*}] => { &[$($tt)*] as _ };
// starting matcher
[$($tt:tt),*] => {
attrs!(@ { $($tt)* } { "allow", "cfg", "cfg_attr", "deny", "forbid", "warn" })
};
}
#[rustfmt::skip]
static KIND_TO_ATTRIBUTES: Lazy<FxHashMap<SyntaxKind, &[&str]>> = Lazy::new(|| {
use SyntaxKind::*;
std::array::IntoIter::new([
(
SOURCE_FILE,
attrs!(
item,
"crate_name", "feature", "no_implicit_prelude", "no_main", "no_std",
"recursion_limit", "type_length_limit", "windows_subsystem"
),
),
(MODULE, attrs!(item, "macro_use", "no_implicit_prelude", "path")),
(ITEM_LIST, attrs!(item, "no_implicit_prelude")),
(MACRO_RULES, attrs!(item, "macro_export", "macro_use")),
(MACRO_DEF, attrs!(item)),
(EXTERN_CRATE, attrs!(item, "macro_use", "no_link")),
(USE, attrs!(item)),
(TYPE_ALIAS, attrs!(item)),
(STRUCT, attrs!(item, adt, "non_exhaustive")),
(ENUM, attrs!(item, adt, "non_exhaustive")),
(UNION, attrs!(item, adt)),
(CONST, attrs!(item)),
(
FN,
attrs!(
item, linkable,
"cold", "ignore", "inline", "must_use", "panic_handler", "proc_macro",
"proc_macro_derive", "proc_macro_attribute", "should_panic", "target_feature",
"test", "track_caller"
),
),
(STATIC, attrs!(item, linkable, "global_allocator", "used")),
(TRAIT, attrs!(item, "must_use")),
(IMPL, attrs!(item, "automatically_derived")),
(ASSOC_ITEM_LIST, attrs!(item)),
(EXTERN_BLOCK, attrs!(item, "link")),
(EXTERN_ITEM_LIST, attrs!(item, "link")),
(MACRO_CALL, attrs!()),
(SELF_PARAM, attrs!()),
(PARAM, attrs!()),
(RECORD_FIELD, attrs!()),
(VARIANT, attrs!("non_exhaustive")),
(TYPE_PARAM, attrs!()),
(CONST_PARAM, attrs!()),
(LIFETIME_PARAM, attrs!()),
(LET_STMT, attrs!()),
(EXPR_STMT, attrs!()),
(LITERAL, attrs!()),
(RECORD_EXPR_FIELD_LIST, attrs!()),
(RECORD_EXPR_FIELD, attrs!()),
(MATCH_ARM_LIST, attrs!()),
(MATCH_ARM, attrs!()),
(IDENT_PAT, attrs!()),
(RECORD_PAT_FIELD, attrs!()),
])
.collect()
});
const EXPR_ATTRIBUTES: &[&str] = attrs!();
/// <https://doc.rust-lang.org/reference/attributes.html#built-in-attributes-index>
// Keep these sorted for the binary search!
const ATTRIBUTES: &[AttrCompletion] = &[
attr("allow(…)", Some("allow"), Some("allow(${0:lint})")),
attr("automatically_derived", None, None),
attr("cfg(…)", Some("cfg"), Some("cfg(${0:predicate})")),
attr("cfg_attr(…)", Some("cfg_attr"), Some("cfg_attr(${1:predicate}, ${0:attr})")),
attr("cold", None, None),
attr(r#"crate_name = """#, Some("crate_name"), Some(r#"crate_name = "${0:crate_name}""#))
.prefer_inner(),
attr("deny(…)", Some("deny"), Some("deny(${0:lint})")),
attr(r#"deprecated"#, Some("deprecated"), Some(r#"deprecated"#)),
attr("derive(…)", Some("derive"), Some(r#"derive(${0:Debug})"#)),
attr(r#"doc = "…""#, Some("doc"), Some(r#"doc = "${0:docs}""#)),
attr(r#"doc(alias = "…")"#, Some("docalias"), Some(r#"doc(alias = "${0:docs}")"#)),
attr(r#"doc(hidden)"#, Some("dochidden"), Some(r#"doc(hidden)"#)),
attr(
r#"export_name = "…""#,
Some("export_name"),
Some(r#"export_name = "${0:exported_symbol_name}""#),
),
attr("feature(…)", Some("feature"), Some("feature(${0:flag})")).prefer_inner(),
attr("forbid(…)", Some("forbid"), Some("forbid(${0:lint})")),
attr("global_allocator", None, None),
attr(r#"ignore = "…""#, Some("ignore"), Some(r#"ignore = "${0:reason}""#)),
attr("inline", Some("inline"), Some("inline")),
attr("link", None, None),
attr(r#"link_name = "…""#, Some("link_name"), Some(r#"link_name = "${0:symbol_name}""#)),
attr(
r#"link_section = "…""#,
Some("link_section"),
Some(r#"link_section = "${0:section_name}""#),
),
attr("macro_export", None, None),
attr("macro_use", None, None),
attr(r#"must_use"#, Some("must_use"), Some(r#"must_use"#)),
attr("no_implicit_prelude", None, None).prefer_inner(),
attr("no_link", None, None).prefer_inner(),
attr("no_main", None, None).prefer_inner(),
attr("no_mangle", None, None),
attr("no_std", None, None).prefer_inner(),
attr("non_exhaustive", None, None),
attr("panic_handler", None, None),
attr(r#"path = "…""#, Some("path"), Some(r#"path ="${0:path}""#)),
attr("proc_macro", None, None),
attr("proc_macro_attribute", None, None),
attr("proc_macro_derive(…)", Some("proc_macro_derive"), Some("proc_macro_derive(${0:Trait})")),
attr("recursion_limit = …", Some("recursion_limit"), Some("recursion_limit = ${0:128}"))
.prefer_inner(),
attr("repr(…)", Some("repr"), Some("repr(${0:C})")),
attr("should_panic", Some("should_panic"), Some(r#"should_panic"#)),
attr(
r#"target_feature = "…""#,
Some("target_feature"),
Some(r#"target_feature = "${0:feature}""#),
),
attr("test", None, None),
attr("track_caller", None, None),
attr("type_length_limit = …", Some("type_length_limit"), Some("type_length_limit = ${0:128}"))
.prefer_inner(),
attr("used", None, None),
attr("warn(…)", Some("warn"), Some("warn(${0:lint})")),
attr(
r#"windows_subsystem = "…""#,
Some("windows_subsystem"),
Some(r#"windows_subsystem = "${0:subsystem}""#),
)
.prefer_inner(),
];
fn parse_comma_sep_input(derive_input: ast::TokenTree) -> Option<FxHashSet<String>> {
let (l_paren, r_paren) = derive_input.l_paren_token().zip(derive_input.r_paren_token())?;
let mut input_derives = FxHashSet::default();
let mut tokens = derive_input
.syntax()
.children_with_tokens()
.filter_map(NodeOrToken::into_token)
.skip_while(|token| token != &l_paren)
.skip(1)
.take_while(|token| token != &r_paren)
.peekable();
let mut input = String::new();
while tokens.peek().is_some() {
for token in tokens.by_ref().take_while(|t| t.kind() != T![,]) {
input.push_str(token.text());
}
if !input.is_empty() {
input_derives.insert(input.trim().to_owned());
}
input.clear();
}
Some(input_derives)
}
#[test]
fn attributes_are_sorted() {
let mut attrs = ATTRIBUTES.iter().map(|attr| attr.key());
let mut prev = attrs.next().unwrap();
attrs.for_each(|next| {
assert!(
prev < next,
r#"ATTRIBUTES array is not sorted, "{}" should come after "{}""#,
prev,
next
);
prev = next;
});
}