mod tags;
mod html;
mod injection;
#[cfg(test)]
mod tests;
use hir::{Name, Semantics};
use ra_ide_db::{
defs::{classify_name, classify_name_ref, Definition, NameClass, NameRefClass},
RootDatabase,
};
use ra_prof::profile;
use ra_syntax::{
ast::{self, HasFormatSpecifier},
AstNode, AstToken, Direction, NodeOrToken, SyntaxElement,
SyntaxKind::*,
TextRange, WalkEvent, T,
};
use rustc_hash::FxHashMap;
use crate::FileId;
use ast::FormatSpecifier;
pub(crate) use html::highlight_as_html;
pub use tags::{Highlight, HighlightModifier, HighlightModifiers, HighlightTag};
#[derive(Debug, Clone)]
pub struct HighlightedRange {
pub range: TextRange,
pub highlight: Highlight,
pub binding_hash: Option<u64>,
}
// Feature: Semantic Syntax Highlighting
//
// rust-analyzer highlights the code semantically.
// For example, `bar` in `foo::Bar` might be colored differently depending on whether `Bar` is an enum or a trait.
// rust-analyzer does not specify colors directly, instead it assigns tag (like `struct`) and a set of modifiers (like `declaration`) to each token.
// It's up to the client to map those to specific colors.
//
// The general rule is that a reference to an entity gets colored the same way as the entity itself.
// We also give special modifier for `mut` and `&mut` local variables.
pub(crate) fn highlight(
db: &RootDatabase,
file_id: FileId,
range_to_highlight: Option<TextRange>,
syntactic_name_ref_highlighting: bool,
) -> Vec<HighlightedRange> {
let _p = profile("highlight");
let sema = Semantics::new(db);
// Determine the root based on the given range.
let (root, range_to_highlight) = {
let source_file = sema.parse(file_id);
match range_to_highlight {
Some(range) => {
let node = match source_file.syntax().covering_element(range) {
NodeOrToken::Node(it) => it,
NodeOrToken::Token(it) => it.parent(),
};
(node, range)
}
None => (source_file.syntax().clone(), source_file.syntax().text_range()),
}
};
let mut bindings_shadow_count: FxHashMap<Name, u32> = FxHashMap::default();
// We use a stack for the DFS traversal below.
// When we leave a node, the we use it to flatten the highlighted ranges.
let mut stack = HighlightedRangeStack::new();
let mut current_macro_call: Option<ast::MacroCall> = None;
let mut format_string: Option<SyntaxElement> = None;
// Walk all nodes, keeping track of whether we are inside a macro or not.
// If in macro, expand it first and highlight the expanded code.
for event in root.preorder_with_tokens() {
match &event {
WalkEvent::Enter(_) => stack.push(),
WalkEvent::Leave(_) => stack.pop(),
};
let event_range = match &event {
WalkEvent::Enter(it) => it.text_range(),
WalkEvent::Leave(it) => it.text_range(),
};
// Element outside of the viewport, no need to highlight
if range_to_highlight.intersect(event_range).is_none() {
continue;
}
// Track "inside macro" state
match event.clone().map(|it| it.into_node().and_then(ast::MacroCall::cast)) {
WalkEvent::Enter(Some(mc)) => {
current_macro_call = Some(mc.clone());
if let Some(range) = macro_call_range(&mc) {
stack.add(HighlightedRange {
range,
highlight: HighlightTag::Macro.into(),
binding_hash: None,
});
}
if let Some(name) = mc.is_macro_rules() {
if let Some((highlight, binding_hash)) = highlight_element(
&sema,
&mut bindings_shadow_count,
syntactic_name_ref_highlighting,
name.syntax().clone().into(),
) {
stack.add(HighlightedRange {
range: name.syntax().text_range(),
highlight,
binding_hash,
});
}
}
continue;
}
WalkEvent::Leave(Some(mc)) => {
assert!(current_macro_call == Some(mc));
current_macro_call = None;
format_string = None;
}
_ => (),
}
// Check for Rust code in documentation
match &event {
WalkEvent::Leave(NodeOrToken::Node(node)) => {
if let Some((doctest, range_mapping, new_comments)) =
injection::extract_doc_comments(node)
{
injection::highlight_doc_comment(
doctest,
range_mapping,
new_comments,
&mut stack,
);
}
}
_ => (),
}
let element = match event {
WalkEvent::Enter(it) => it,
WalkEvent::Leave(_) => continue,
};
let range = element.text_range();
let element_to_highlight = if current_macro_call.is_some() && element.kind() != COMMENT {
// Inside a macro -- expand it first
let token = match element.clone().into_token() {
Some(it) if it.parent().kind() == TOKEN_TREE => it,
_ => continue,
};
let token = sema.descend_into_macros(token.clone());
let parent = token.parent();
// Check if macro takes a format string and remember it for highlighting later.
// The macros that accept a format string expand to a compiler builtin macros
// `format_args` and `format_args_nl`.
if let Some(name) = parent
.parent()
.and_then(ast::MacroCall::cast)
.and_then(|mc| mc.path())
.and_then(|p| p.segment())
.and_then(|s| s.name_ref())
{
match name.text().as_str() {
"format_args" | "format_args_nl" => {
format_string = parent
.children_with_tokens()
.filter(|t| t.kind() != WHITESPACE)
.nth(1)
.filter(|e| {
ast::String::can_cast(e.kind())
|| ast::RawString::can_cast(e.kind())
})
}
_ => {}
}
}
// We only care Name and Name_ref
match (token.kind(), parent.kind()) {
(IDENT, NAME) | (IDENT, NAME_REF) => parent.into(),
_ => token.into(),
}
} else {
element.clone()
};
if let Some(token) = element.as_token().cloned().and_then(ast::RawString::cast) {
let expanded = element_to_highlight.as_token().unwrap().clone();
if injection::highlight_injection(&mut stack, &sema, token, expanded).is_some() {
continue;
}
}
let is_format_string = format_string.as_ref() == Some(&element_to_highlight);
if let Some((highlight, binding_hash)) = highlight_element(
&sema,
&mut bindings_shadow_count,
syntactic_name_ref_highlighting,
element_to_highlight.clone(),
) {
stack.add(HighlightedRange { range, highlight, binding_hash });
if let Some(string) =
element_to_highlight.as_token().cloned().and_then(ast::String::cast)
{
if is_format_string {
stack.push();
string.lex_format_specifier(|piece_range, kind| {
if let Some(highlight) = highlight_format_specifier(kind) {
stack.add(HighlightedRange {
range: piece_range + range.start(),
highlight: highlight.into(),
binding_hash: None,
});
}
});
stack.pop();
}
// Highlight escape sequences
if let Some(char_ranges) = string.char_ranges() {
stack.push();
for (piece_range, _) in char_ranges.iter().filter(|(_, char)| char.is_ok()) {
if string.text()[piece_range.start().into()..].starts_with('\\') {
stack.add(HighlightedRange {
range: piece_range + range.start(),
highlight: HighlightTag::EscapeSequence.into(),
binding_hash: None,
});
}
}
stack.pop_and_inject(None);
}
} else if let Some(string) =
element_to_highlight.as_token().cloned().and_then(ast::RawString::cast)
{
if is_format_string {
stack.push();
string.lex_format_specifier(|piece_range, kind| {
if let Some(highlight) = highlight_format_specifier(kind) {
stack.add(HighlightedRange {
range: piece_range + range.start(),
highlight: highlight.into(),
binding_hash: None,
});
}
});
stack.pop();
}
}
}
}
stack.flattened()
}
#[derive(Debug)]
struct HighlightedRangeStack {
stack: Vec<Vec<HighlightedRange>>,
}
/// We use a stack to implement the flattening logic for the highlighted
/// syntax ranges.
impl HighlightedRangeStack {
fn new() -> Self {
Self { stack: vec![Vec::new()] }
}
fn push(&mut self) {
self.stack.push(Vec::new());
}
/// Flattens the highlighted ranges.
///
/// For example `#[cfg(feature = "foo")]` contains the nested ranges:
/// 1) parent-range: Attribute [0, 23)
/// 2) child-range: String [16, 21)
///
/// The following code implements the flattening, for our example this results to:
/// `[Attribute [0, 16), String [16, 21), Attribute [21, 23)]`
fn pop(&mut self) {
let children = self.stack.pop().unwrap();
let prev = self.stack.last_mut().unwrap();
let needs_flattening = !children.is_empty()
&& !prev.is_empty()
&& prev.last().unwrap().range.contains_range(children.first().unwrap().range);
if !needs_flattening {
prev.extend(children);
} else {
let mut parent = prev.pop().unwrap();
for ele in children {
assert!(parent.range.contains_range(ele.range));
let cloned = Self::intersect(&mut parent, &ele);
if !parent.range.is_empty() {
prev.push(parent);
}
prev.push(ele);
parent = cloned;
}
if !parent.range.is_empty() {
prev.push(parent);
}
}
}
/// Intersects the `HighlightedRange` `parent` with `child`.
/// `parent` is mutated in place, becoming the range before `child`.
/// Returns the range (of the same type as `parent`) *after* `child`.
fn intersect(parent: &mut HighlightedRange, child: &HighlightedRange) -> HighlightedRange {
assert!(parent.range.contains_range(child.range));
let mut cloned = parent.clone();
parent.range = TextRange::new(parent.range.start(), child.range.start());
cloned.range = TextRange::new(child.range.end(), cloned.range.end());
cloned
}
/// Remove the `HighlightRange` of `parent` that's currently covered by `child`.
fn intersect_partial(parent: &mut HighlightedRange, child: &HighlightedRange) {
assert!(
parent.range.start() <= child.range.start()
&& parent.range.end() >= child.range.start()
&& child.range.end() > parent.range.end()
);
parent.range = TextRange::new(parent.range.start(), child.range.start());
}
/// Similar to `pop`, but can modify arbitrary prior ranges (where `pop`)
/// can only modify the last range currently on the stack.
/// Can be used to do injections that span multiple ranges, like the
/// doctest injection below.
/// If `overwrite_parent` is non-optional, the highlighting of the parent range
/// is overwritten with the argument.
///
/// Note that `pop` can be simulated by `pop_and_inject(false)` but the
/// latter is computationally more expensive.
fn pop_and_inject(&mut self, overwrite_parent: Option<Highlight>) {
let mut children = self.stack.pop().unwrap();
let prev = self.stack.last_mut().unwrap();
children.sort_by_key(|range| range.range.start());
prev.sort_by_key(|range| range.range.start());
for child in children {
if let Some(idx) =
prev.iter().position(|parent| parent.range.contains_range(child.range))
{
if let Some(tag) = overwrite_parent {
prev[idx].highlight = tag;
}
let cloned = Self::intersect(&mut prev[idx], &child);
let insert_idx = if prev[idx].range.is_empty() {
prev.remove(idx);
idx
} else {
idx + 1
};
prev.insert(insert_idx, child);
if !cloned.range.is_empty() {
prev.insert(insert_idx + 1, cloned);
}
} else {
let maybe_idx =
prev.iter().position(|parent| parent.range.contains(child.range.start()));
match (overwrite_parent, maybe_idx) {
(Some(_), Some(idx)) => {
Self::intersect_partial(&mut prev[idx], &child);
let insert_idx = if prev[idx].range.is_empty() {
prev.remove(idx);
idx
} else {
idx + 1
};
prev.insert(insert_idx, child);
}
(_, None) => {
let idx = prev
.binary_search_by_key(&child.range.start(), |range| range.range.start())
.unwrap_or_else(|x| x);
prev.insert(idx, child);
}
_ => {
unreachable!("child range should be completely contained in parent range");
}
}
}
}
}
fn add(&mut self, range: HighlightedRange) {
self.stack
.last_mut()
.expect("during DFS traversal, the stack must not be empty")
.push(range)
}
fn flattened(mut self) -> Vec<HighlightedRange> {
assert_eq!(
self.stack.len(),
1,
"after DFS traversal, the stack should only contain a single element"
);
let mut res = self.stack.pop().unwrap();
res.sort_by_key(|range| range.range.start());
// Check that ranges are sorted and disjoint
assert!(res
.iter()
.zip(res.iter().skip(1))
.all(|(left, right)| left.range.end() <= right.range.start()));
res
}
}
fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HighlightTag> {
Some(match kind {
FormatSpecifier::Open
| FormatSpecifier::Close
| FormatSpecifier::Colon
| FormatSpecifier::Fill
| FormatSpecifier::Align
| FormatSpecifier::Sign
| FormatSpecifier::NumberSign
| FormatSpecifier::DollarSign
| FormatSpecifier::Dot
| FormatSpecifier::Asterisk
| FormatSpecifier::QuestionMark => HighlightTag::FormatSpecifier,
FormatSpecifier::Integer | FormatSpecifier::Zero => HighlightTag::NumericLiteral,
FormatSpecifier::Identifier => HighlightTag::Local,
})
}
fn macro_call_range(macro_call: &ast::MacroCall) -> Option<TextRange> {
let path = macro_call.path()?;
let name_ref = path.segment()?.name_ref()?;
let range_start = name_ref.syntax().text_range().start();
let mut range_end = name_ref.syntax().text_range().end();
for sibling in path.syntax().siblings_with_tokens(Direction::Next) {
match sibling.kind() {
T![!] | IDENT => range_end = sibling.text_range().end(),
_ => (),
}
}
Some(TextRange::new(range_start, range_end))
}
fn highlight_element(
sema: &Semantics<RootDatabase>,
bindings_shadow_count: &mut FxHashMap<Name, u32>,
syntactic_name_ref_highlighting: bool,
element: SyntaxElement,
) -> Option<(Highlight, Option<u64>)> {
let db = sema.db;
let mut binding_hash = None;
let highlight: Highlight = match element.kind() {
FN_DEF => {
bindings_shadow_count.clear();
return None;
}
// Highlight definitions depending on the "type" of the definition.
NAME => {
let name = element.into_node().and_then(ast::Name::cast).unwrap();
let name_kind = classify_name(sema, &name);
if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
if let Some(name) = local.name(db) {
let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
*shadow_count += 1;
binding_hash = Some(calc_binding_hash(&name, *shadow_count))
}
};
match name_kind {
Some(NameClass::Definition(def)) => {
highlight_name(db, def) | HighlightModifier::Definition
}
Some(NameClass::ConstReference(def)) => highlight_name(db, def),
Some(NameClass::FieldShorthand { .. }) => HighlightTag::Field.into(),
None => highlight_name_by_syntax(name) | HighlightModifier::Definition,
}
}
// Highlight references like the definitions they resolve to
NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
Highlight::from(HighlightTag::Function) | HighlightModifier::Attribute
}
NAME_REF => {
let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
match classify_name_ref(sema, &name_ref) {
Some(name_kind) => match name_kind {
NameRefClass::Definition(def) => {
if let Definition::Local(local) = &def {
if let Some(name) = local.name(db) {
let shadow_count =
bindings_shadow_count.entry(name.clone()).or_default();
binding_hash = Some(calc_binding_hash(&name, *shadow_count))
}
};
highlight_name(db, def)
}
NameRefClass::FieldShorthand { .. } => HighlightTag::Field.into(),
},
None if syntactic_name_ref_highlighting => highlight_name_ref_by_syntax(name_ref),
None => HighlightTag::UnresolvedReference.into(),
}
}
// Simple token-based highlighting
COMMENT => {
let comment = element.into_token().and_then(ast::Comment::cast)?;
let h = HighlightTag::Comment;
match comment.kind().doc {
Some(_) => h | HighlightModifier::Documentation,
None => h.into(),
}
}
STRING | RAW_STRING | RAW_BYTE_STRING | BYTE_STRING => HighlightTag::StringLiteral.into(),
ATTR => HighlightTag::Attribute.into(),
INT_NUMBER | FLOAT_NUMBER => HighlightTag::NumericLiteral.into(),
BYTE => HighlightTag::ByteLiteral.into(),
CHAR => HighlightTag::CharLiteral.into(),
QUESTION => Highlight::new(HighlightTag::Operator) | HighlightModifier::ControlFlow,
LIFETIME => {
let h = Highlight::new(HighlightTag::Lifetime);
match element.parent().map(|it| it.kind()) {
Some(LIFETIME_PARAM) | Some(LABEL) => h | HighlightModifier::Definition,
_ => h,
}
}
T![*] => {
let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
let expr = prefix_expr.expr()?;
let ty = sema.type_of_expr(&expr)?;
if !ty.is_raw_ptr() {
return None;
} else {
HighlightTag::Operator | HighlightModifier::Unsafe
}
}
T![!] if element.parent().and_then(ast::MacroCall::cast).is_some() => {
Highlight::new(HighlightTag::Macro)
}
k if k.is_keyword() => {
let h = Highlight::new(HighlightTag::Keyword);
match k {
T![break]
| T![continue]
| T![else]
| T![if]
| T![loop]
| T![match]
| T![return]
| T![while]
| T![in] => h | HighlightModifier::ControlFlow,
T![for] if !is_child_of_impl(element) => h | HighlightModifier::ControlFlow,
T![unsafe] => h | HighlightModifier::Unsafe,
T![true] | T![false] => HighlightTag::BoolLiteral.into(),
T![self] => HighlightTag::SelfKeyword.into(),
_ => h,
}
}
_ => return None,
};
return Some((highlight, binding_hash));
fn calc_binding_hash(name: &Name, shadow_count: u32) -> u64 {
fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
use std::{collections::hash_map::DefaultHasher, hash::Hasher};
let mut hasher = DefaultHasher::new();
x.hash(&mut hasher);
hasher.finish()
}
hash((name, shadow_count))
}
}
fn is_child_of_impl(element: SyntaxElement) -> bool {
match element.parent() {
Some(e) => e.kind() == IMPL_DEF,
_ => false,
}
}
fn highlight_name(db: &RootDatabase, def: Definition) -> Highlight {
match def {
Definition::Macro(_) => HighlightTag::Macro,
Definition::Field(_) => HighlightTag::Field,
Definition::ModuleDef(def) => match def {
hir::ModuleDef::Module(_) => HighlightTag::Module,
hir::ModuleDef::Function(func) => {
let mut h = HighlightTag::Function.into();
if func.is_unsafe(db) {
h |= HighlightModifier::Unsafe;
}
return h;
}
hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HighlightTag::Struct,
hir::ModuleDef::Adt(hir::Adt::Enum(_)) => HighlightTag::Enum,
hir::ModuleDef::Adt(hir::Adt::Union(_)) => HighlightTag::Union,
hir::ModuleDef::EnumVariant(_) => HighlightTag::EnumVariant,
hir::ModuleDef::Const(_) => HighlightTag::Constant,
hir::ModuleDef::Trait(_) => HighlightTag::Trait,
hir::ModuleDef::TypeAlias(_) => HighlightTag::TypeAlias,
hir::ModuleDef::BuiltinType(_) => HighlightTag::BuiltinType,
hir::ModuleDef::Static(s) => {
let mut h = Highlight::new(HighlightTag::Static);
if s.is_mut(db) {
h |= HighlightModifier::Mutable;
}
return h;
}
},
Definition::SelfType(_) => HighlightTag::SelfType,
Definition::TypeParam(_) => HighlightTag::TypeParam,
// FIXME: distinguish between locals and parameters
Definition::Local(local) => {
let mut h = Highlight::new(HighlightTag::Local);
if local.is_mut(db) || local.ty(db).is_mutable_reference() {
h |= HighlightModifier::Mutable;
}
return h;
}
}
.into()
}
fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
let default = HighlightTag::UnresolvedReference;
let parent = match name.syntax().parent() {
Some(it) => it,
_ => return default.into(),
};
let tag = match parent.kind() {
STRUCT_DEF => HighlightTag::Struct,
ENUM_DEF => HighlightTag::Enum,
UNION_DEF => HighlightTag::Union,
TRAIT_DEF => HighlightTag::Trait,
TYPE_ALIAS_DEF => HighlightTag::TypeAlias,
TYPE_PARAM => HighlightTag::TypeParam,
RECORD_FIELD_DEF => HighlightTag::Field,
MODULE => HighlightTag::Module,
FN_DEF => HighlightTag::Function,
CONST_DEF => HighlightTag::Constant,
STATIC_DEF => HighlightTag::Static,
ENUM_VARIANT => HighlightTag::EnumVariant,
BIND_PAT => HighlightTag::Local,
_ => default,
};
tag.into()
}
fn highlight_name_ref_by_syntax(name: ast::NameRef) -> Highlight {
let default = HighlightTag::UnresolvedReference;
let parent = match name.syntax().parent() {
Some(it) => it,
_ => return default.into(),
};
let tag = match parent.kind() {
METHOD_CALL_EXPR => HighlightTag::Function,
FIELD_EXPR => HighlightTag::Field,
PATH_SEGMENT => {
let path = match parent.parent().and_then(ast::Path::cast) {
Some(it) => it,
_ => return default.into(),
};
let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
Some(it) => it,
_ => {
// within path, decide whether it is module or adt by checking for uppercase name
return if name.text().chars().next().unwrap_or_default().is_uppercase() {
HighlightTag::Struct
} else {
HighlightTag::Module
}
.into();
}
};
let parent = match expr.syntax().parent() {
Some(it) => it,
None => return default.into(),
};
match parent.kind() {
CALL_EXPR => HighlightTag::Function,
_ => {
if name.text().chars().next().unwrap_or_default().is_uppercase() {
HighlightTag::Struct
} else {
HighlightTag::Constant
}
}
}
}
_ => default,
};
tag.into()
}