7 use hir::{Name, Semantics};
9 defs::{classify_name, classify_name_ref, Definition, NameClass, NameRefClass},
14 ast::{self, HasFormatSpecifier},
15 AstNode, AstToken, Direction, NodeOrToken, SyntaxElement,
17 TextRange, WalkEvent, T,
19 use rustc_hash::FxHashMap;
23 use ast::FormatSpecifier;
24 pub(crate) use html::highlight_as_html;
25 pub use tags::{Highlight, HighlightModifier, HighlightModifiers, HighlightTag};
27 #[derive(Debug, Clone)]
28 pub struct HighlightedRange {
30 pub highlight: Highlight,
31 pub binding_hash: Option<u64>,
34 // Feature: Semantic Syntax Highlighting
36 // rust-analyzer highlights the code semantically.
37 // For example, `bar` in `foo::Bar` might be colored differently depending on whether `Bar` is an enum or a trait.
38 // rust-analyzer does not specify colors directly, instead it assigns tag (like `struct`) and a set of modifiers (like `declaration`) to each token.
39 // It's up to the client to map those to specific colors.
41 // The general rule is that a reference to an entity gets colored the same way as the entity itself.
42 // We also give special modifier for `mut` and `&mut` local variables.
43 pub(crate) fn highlight(
46 range_to_highlight: Option<TextRange>,
47 syntactic_name_ref_highlighting: bool,
48 ) -> Vec<HighlightedRange> {
49 let _p = profile("highlight");
50 let sema = Semantics::new(db);
52 // Determine the root based on the given range.
53 let (root, range_to_highlight) = {
54 let source_file = sema.parse(file_id);
55 match range_to_highlight {
57 let node = match source_file.syntax().covering_element(range) {
58 NodeOrToken::Node(it) => it,
59 NodeOrToken::Token(it) => it.parent(),
63 None => (source_file.syntax().clone(), source_file.syntax().text_range()),
67 let mut bindings_shadow_count: FxHashMap<Name, u32> = FxHashMap::default();
68 // We use a stack for the DFS traversal below.
69 // When we leave a node, the we use it to flatten the highlighted ranges.
70 let mut stack = HighlightedRangeStack::new();
72 let mut current_macro_call: Option<ast::MacroCall> = None;
73 let mut format_string: Option<SyntaxElement> = None;
75 // Walk all nodes, keeping track of whether we are inside a macro or not.
76 // If in macro, expand it first and highlight the expanded code.
77 for event in root.preorder_with_tokens() {
79 WalkEvent::Enter(_) => stack.push(),
80 WalkEvent::Leave(_) => stack.pop(),
83 let event_range = match &event {
84 WalkEvent::Enter(it) => it.text_range(),
85 WalkEvent::Leave(it) => it.text_range(),
88 // Element outside of the viewport, no need to highlight
89 if range_to_highlight.intersect(event_range).is_none() {
93 // Track "inside macro" state
94 match event.clone().map(|it| it.into_node().and_then(ast::MacroCall::cast)) {
95 WalkEvent::Enter(Some(mc)) => {
96 current_macro_call = Some(mc.clone());
97 if let Some(range) = macro_call_range(&mc) {
98 stack.add(HighlightedRange {
100 highlight: HighlightTag::Macro.into(),
104 if let Some(name) = mc.is_macro_rules() {
105 if let Some((highlight, binding_hash)) = highlight_element(
107 &mut bindings_shadow_count,
108 syntactic_name_ref_highlighting,
109 name.syntax().clone().into(),
111 stack.add(HighlightedRange {
112 range: name.syntax().text_range(),
120 WalkEvent::Leave(Some(mc)) => {
121 assert!(current_macro_call == Some(mc));
122 current_macro_call = None;
123 format_string = None;
128 // Check for Rust code in documentation
130 WalkEvent::Leave(NodeOrToken::Node(node)) => {
131 if let Some((doctest, range_mapping, new_comments)) =
132 injection::extract_doc_comments(node)
134 injection::highlight_doc_comment(
145 let element = match event {
146 WalkEvent::Enter(it) => it,
147 WalkEvent::Leave(_) => continue,
150 let range = element.text_range();
152 let element_to_highlight = if current_macro_call.is_some() && element.kind() != COMMENT {
153 // Inside a macro -- expand it first
154 let token = match element.clone().into_token() {
155 Some(it) if it.parent().kind() == TOKEN_TREE => it,
158 let token = sema.descend_into_macros(token.clone());
159 let parent = token.parent();
161 // Check if macro takes a format string and remember it for highlighting later.
162 // The macros that accept a format string expand to a compiler builtin macros
163 // `format_args` and `format_args_nl`.
164 if let Some(name) = parent
166 .and_then(ast::MacroCall::cast)
167 .and_then(|mc| mc.path())
168 .and_then(|p| p.segment())
169 .and_then(|s| s.name_ref())
171 match name.text().as_str() {
172 "format_args" | "format_args_nl" => {
173 format_string = parent
174 .children_with_tokens()
175 .filter(|t| t.kind() != WHITESPACE)
178 ast::String::can_cast(e.kind())
179 || ast::RawString::can_cast(e.kind())
186 // We only care Name and Name_ref
187 match (token.kind(), parent.kind()) {
188 (IDENT, NAME) | (IDENT, NAME_REF) => parent.into(),
195 if let Some(token) = element.as_token().cloned().and_then(ast::RawString::cast) {
196 let expanded = element_to_highlight.as_token().unwrap().clone();
197 if injection::highlight_injection(&mut stack, &sema, token, expanded).is_some() {
202 let is_format_string = format_string.as_ref() == Some(&element_to_highlight);
204 if let Some((highlight, binding_hash)) = highlight_element(
206 &mut bindings_shadow_count,
207 syntactic_name_ref_highlighting,
208 element_to_highlight.clone(),
210 stack.add(HighlightedRange { range, highlight, binding_hash });
211 if let Some(string) =
212 element_to_highlight.as_token().cloned().and_then(ast::String::cast)
214 if is_format_string {
216 string.lex_format_specifier(|piece_range, kind| {
217 if let Some(highlight) = highlight_format_specifier(kind) {
218 stack.add(HighlightedRange {
219 range: piece_range + range.start(),
220 highlight: highlight.into(),
227 // Highlight escape sequences
228 if let Some(char_ranges) = string.char_ranges() {
230 for (piece_range, _) in char_ranges.iter().filter(|(_, char)| char.is_ok()) {
231 if string.text()[piece_range.start().into()..].starts_with('\\') {
232 stack.add(HighlightedRange {
233 range: piece_range + range.start(),
234 highlight: HighlightTag::EscapeSequence.into(),
239 stack.pop_and_inject(false);
241 } else if let Some(string) =
242 element_to_highlight.as_token().cloned().and_then(ast::RawString::cast)
244 if is_format_string {
246 string.lex_format_specifier(|piece_range, kind| {
247 if let Some(highlight) = highlight_format_specifier(kind) {
248 stack.add(HighlightedRange {
249 range: piece_range + range.start(),
250 highlight: highlight.into(),
265 struct HighlightedRangeStack {
266 stack: Vec<Vec<HighlightedRange>>,
269 /// We use a stack to implement the flattening logic for the highlighted
271 impl HighlightedRangeStack {
273 Self { stack: vec![Vec::new()] }
277 self.stack.push(Vec::new());
280 /// Flattens the highlighted ranges.
282 /// For example `#[cfg(feature = "foo")]` contains the nested ranges:
283 /// 1) parent-range: Attribute [0, 23)
284 /// 2) child-range: String [16, 21)
286 /// The following code implements the flattening, for our example this results to:
287 /// `[Attribute [0, 16), String [16, 21), Attribute [21, 23)]`
289 let children = self.stack.pop().unwrap();
290 let prev = self.stack.last_mut().unwrap();
291 let needs_flattening = !children.is_empty()
293 && prev.last().unwrap().range.contains_range(children.first().unwrap().range);
294 if !needs_flattening {
295 prev.extend(children);
297 let mut parent = prev.pop().unwrap();
298 for ele in children {
299 assert!(parent.range.contains_range(ele.range));
301 let cloned = Self::intersect(&mut parent, &ele);
302 if !parent.range.is_empty() {
308 if !parent.range.is_empty() {
314 /// Intersects the `HighlightedRange` `parent` with `child`.
315 /// `parent` is mutated in place, becoming the range before `child`.
316 /// Returns the range (of the same type as `parent`) *after* `child`.
317 fn intersect(parent: &mut HighlightedRange, child: &HighlightedRange) -> HighlightedRange {
318 assert!(parent.range.contains_range(child.range));
320 let mut cloned = parent.clone();
321 parent.range = TextRange::new(parent.range.start(), child.range.start());
322 cloned.range = TextRange::new(child.range.end(), cloned.range.end());
327 /// Similar to `pop`, but can modify arbitrary prior ranges (where `pop`)
328 /// can only modify the last range currently on the stack.
329 /// Can be used to do injections that span multiple ranges, like the
330 /// doctest injection below.
331 /// If `delete` is set to true, the parent range is deleted instead of
334 /// Note that `pop` can be simulated by `pop_and_inject(false)` but the
335 /// latter is computationally more expensive.
336 fn pop_and_inject(&mut self, delete: bool) {
337 let mut children = self.stack.pop().unwrap();
338 let prev = self.stack.last_mut().unwrap();
339 children.sort_by_key(|range| range.range.start());
340 prev.sort_by_key(|range| range.range.start());
342 for child in children {
344 prev.iter().position(|parent| parent.range.contains_range(child.range))
346 let cloned = Self::intersect(&mut prev[idx], &child);
347 let insert_idx = if delete || prev[idx].range.is_empty() {
353 prev.insert(insert_idx, child);
354 if !delete && !cloned.range.is_empty() {
355 prev.insert(insert_idx + 1, cloned);
357 } else if let Some(_idx) =
358 prev.iter().position(|parent| parent.range.contains(child.range.start()))
360 unreachable!("child range should be completely contained in parent range");
363 .binary_search_by_key(&child.range.start(), |range| range.range.start())
364 .unwrap_or_else(|x| x);
365 prev.insert(idx, child);
370 fn add(&mut self, range: HighlightedRange) {
373 .expect("during DFS traversal, the stack must not be empty")
377 fn flattened(mut self) -> Vec<HighlightedRange> {
381 "after DFS traversal, the stack should only contain a single element"
383 let mut res = self.stack.pop().unwrap();
384 res.sort_by_key(|range| range.range.start());
385 // Check that ranges are sorted and disjoint
388 .zip(res.iter().skip(1))
389 .all(|(left, right)| left.range.end() <= right.range.start()));
394 fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HighlightTag> {
396 FormatSpecifier::Open
397 | FormatSpecifier::Close
398 | FormatSpecifier::Colon
399 | FormatSpecifier::Fill
400 | FormatSpecifier::Align
401 | FormatSpecifier::Sign
402 | FormatSpecifier::NumberSign
403 | FormatSpecifier::DollarSign
404 | FormatSpecifier::Dot
405 | FormatSpecifier::Asterisk
406 | FormatSpecifier::QuestionMark => HighlightTag::FormatSpecifier,
407 FormatSpecifier::Integer | FormatSpecifier::Zero => HighlightTag::NumericLiteral,
408 FormatSpecifier::Identifier => HighlightTag::Local,
412 fn macro_call_range(macro_call: &ast::MacroCall) -> Option<TextRange> {
413 let path = macro_call.path()?;
414 let name_ref = path.segment()?.name_ref()?;
416 let range_start = name_ref.syntax().text_range().start();
417 let mut range_end = name_ref.syntax().text_range().end();
418 for sibling in path.syntax().siblings_with_tokens(Direction::Next) {
419 match sibling.kind() {
420 T![!] | IDENT => range_end = sibling.text_range().end(),
425 Some(TextRange::new(range_start, range_end))
428 fn highlight_element(
429 sema: &Semantics<RootDatabase>,
430 bindings_shadow_count: &mut FxHashMap<Name, u32>,
431 syntactic_name_ref_highlighting: bool,
432 element: SyntaxElement,
433 ) -> Option<(Highlight, Option<u64>)> {
435 let mut binding_hash = None;
436 let highlight: Highlight = match element.kind() {
438 bindings_shadow_count.clear();
442 // Highlight definitions depending on the "type" of the definition.
444 let name = element.into_node().and_then(ast::Name::cast).unwrap();
445 let name_kind = classify_name(sema, &name);
447 if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
448 if let Some(name) = local.name(db) {
449 let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
451 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
456 Some(NameClass::Definition(def)) => {
457 highlight_name(db, def) | HighlightModifier::Definition
459 Some(NameClass::ConstReference(def)) => highlight_name(db, def),
460 Some(NameClass::FieldShorthand { .. }) => HighlightTag::Field.into(),
461 None => highlight_name_by_syntax(name) | HighlightModifier::Definition,
465 // Highlight references like the definitions they resolve to
466 NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
467 Highlight::from(HighlightTag::Function) | HighlightModifier::Attribute
470 let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
471 match classify_name_ref(sema, &name_ref) {
472 Some(name_kind) => match name_kind {
473 NameRefClass::Definition(def) => {
474 if let Definition::Local(local) = &def {
475 if let Some(name) = local.name(db) {
477 bindings_shadow_count.entry(name.clone()).or_default();
478 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
481 highlight_name(db, def)
483 NameRefClass::FieldShorthand { .. } => HighlightTag::Field.into(),
485 None if syntactic_name_ref_highlighting => highlight_name_ref_by_syntax(name_ref),
486 None => HighlightTag::UnresolvedReference.into(),
490 // Simple token-based highlighting
492 let comment = element.into_token().and_then(ast::Comment::cast)?;
493 let h = HighlightTag::Comment;
494 match comment.kind().doc {
495 Some(_) => h | HighlightModifier::Documentation,
499 STRING | RAW_STRING | RAW_BYTE_STRING | BYTE_STRING => HighlightTag::StringLiteral.into(),
500 ATTR => HighlightTag::Attribute.into(),
501 INT_NUMBER | FLOAT_NUMBER => HighlightTag::NumericLiteral.into(),
502 BYTE => HighlightTag::ByteLiteral.into(),
503 CHAR => HighlightTag::CharLiteral.into(),
504 QUESTION => Highlight::new(HighlightTag::Operator) | HighlightModifier::ControlFlow,
506 let h = Highlight::new(HighlightTag::Lifetime);
507 match element.parent().map(|it| it.kind()) {
508 Some(LIFETIME_PARAM) | Some(LABEL) => h | HighlightModifier::Definition,
513 let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
515 let expr = prefix_expr.expr()?;
516 let ty = sema.type_of_expr(&expr)?;
517 if !ty.is_raw_ptr() {
521 let mut h = Highlight::new(HighlightTag::Operator);
522 h |= HighlightModifier::Unsafe;
525 T![!] if element.parent().and_then(ast::MacroCall::cast).is_some() => {
526 Highlight::new(HighlightTag::Macro)
529 k if k.is_keyword() => {
530 let h = Highlight::new(HighlightTag::Keyword);
540 | T![in] => h | HighlightModifier::ControlFlow,
541 T![for] if !is_child_of_impl(element) => h | HighlightModifier::ControlFlow,
542 T![unsafe] => h | HighlightModifier::Unsafe,
543 T![true] | T![false] => HighlightTag::BoolLiteral.into(),
544 T![self] => HighlightTag::SelfKeyword.into(),
552 return Some((highlight, binding_hash));
554 fn calc_binding_hash(name: &Name, shadow_count: u32) -> u64 {
555 fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
556 use std::{collections::hash_map::DefaultHasher, hash::Hasher};
558 let mut hasher = DefaultHasher::new();
563 hash((name, shadow_count))
567 fn is_child_of_impl(element: SyntaxElement) -> bool {
568 match element.parent() {
569 Some(e) => e.kind() == IMPL_DEF,
574 fn highlight_name(db: &RootDatabase, def: Definition) -> Highlight {
576 Definition::Macro(_) => HighlightTag::Macro,
577 Definition::Field(_) => HighlightTag::Field,
578 Definition::ModuleDef(def) => match def {
579 hir::ModuleDef::Module(_) => HighlightTag::Module,
580 hir::ModuleDef::Function(func) => {
581 let mut h = HighlightTag::Function.into();
582 if func.is_unsafe(db) {
583 h |= HighlightModifier::Unsafe;
587 hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HighlightTag::Struct,
588 hir::ModuleDef::Adt(hir::Adt::Enum(_)) => HighlightTag::Enum,
589 hir::ModuleDef::Adt(hir::Adt::Union(_)) => HighlightTag::Union,
590 hir::ModuleDef::EnumVariant(_) => HighlightTag::EnumVariant,
591 hir::ModuleDef::Const(_) => HighlightTag::Constant,
592 hir::ModuleDef::Trait(_) => HighlightTag::Trait,
593 hir::ModuleDef::TypeAlias(_) => HighlightTag::TypeAlias,
594 hir::ModuleDef::BuiltinType(_) => HighlightTag::BuiltinType,
595 hir::ModuleDef::Static(s) => {
596 let mut h = Highlight::new(HighlightTag::Static);
598 h |= HighlightModifier::Mutable;
603 Definition::SelfType(_) => HighlightTag::SelfType,
604 Definition::TypeParam(_) => HighlightTag::TypeParam,
605 // FIXME: distinguish between locals and parameters
606 Definition::Local(local) => {
607 let mut h = Highlight::new(HighlightTag::Local);
608 if local.is_mut(db) || local.ty(db).is_mutable_reference() {
609 h |= HighlightModifier::Mutable;
617 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
618 let default = HighlightTag::UnresolvedReference;
620 let parent = match name.syntax().parent() {
622 _ => return default.into(),
625 let tag = match parent.kind() {
626 STRUCT_DEF => HighlightTag::Struct,
627 ENUM_DEF => HighlightTag::Enum,
628 UNION_DEF => HighlightTag::Union,
629 TRAIT_DEF => HighlightTag::Trait,
630 TYPE_ALIAS_DEF => HighlightTag::TypeAlias,
631 TYPE_PARAM => HighlightTag::TypeParam,
632 RECORD_FIELD_DEF => HighlightTag::Field,
633 MODULE => HighlightTag::Module,
634 FN_DEF => HighlightTag::Function,
635 CONST_DEF => HighlightTag::Constant,
636 STATIC_DEF => HighlightTag::Static,
637 ENUM_VARIANT => HighlightTag::EnumVariant,
638 BIND_PAT => HighlightTag::Local,
645 fn highlight_name_ref_by_syntax(name: ast::NameRef) -> Highlight {
646 let default = HighlightTag::UnresolvedReference;
648 let parent = match name.syntax().parent() {
650 _ => return default.into(),
653 let tag = match parent.kind() {
654 METHOD_CALL_EXPR => HighlightTag::Function,
655 FIELD_EXPR => HighlightTag::Field,
657 let path = match parent.parent().and_then(ast::Path::cast) {
659 _ => return default.into(),
661 let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
664 // within path, decide whether it is module or adt by checking for uppercase name
665 return if name.text().chars().next().unwrap_or_default().is_uppercase() {
673 let parent = match expr.syntax().parent() {
675 None => return default.into(),
678 match parent.kind() {
679 CALL_EXPR => HighlightTag::Function,
681 if name.text().chars().next().unwrap_or_default().is_uppercase() {
684 HighlightTag::Constant