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//! This module handles fuzzy-searching of functions, structs and other symbols
//! by name across the whole workspace and dependencies.
//!
//! It works by building an incrementally-updated text-search index of all
//! symbols. The backbone of the index is the **awesome** `fst` crate by
//! @BurntSushi.
//!
//! In a nutshell, you give a set of strings to `fst`, and it builds a
//! finite state machine describing this set of strings. The strings which
//! could fuzzy-match a pattern can also be described by a finite state machine.
//! What is freaking cool is that you can now traverse both state machines in
//! lock-step to enumerate the strings which are both in the input set and
//! fuzz-match the query. Or, more formally, given two languages described by
//! FSTs, one can build a product FST which describes the intersection of the
//! languages.
//!
//! `fst` does not support cheap updating of the index, but it supports unioning
//! of state machines. So, to account for changing source code, we build an FST
//! for each library (which is assumed to never change) and an FST for each Rust
//! file in the current workspace, and run a query against the union of all
//! those FSTs.
use std::{
cmp::Ordering,
fmt,
hash::{Hash, Hasher},
mem,
sync::Arc,
};
use base_db::{
salsa::{self, ParallelDatabase},
SourceDatabaseExt, SourceRootId, Upcast,
};
use fst::{self, Streamer};
use hir::{
db::HirDatabase,
symbols::{FileSymbol, SymbolCollector},
Crate, Module,
};
use rayon::prelude::*;
use rustc_hash::FxHashSet;
use crate::RootDatabase;
#[derive(Debug)]
pub struct Query {
query: String,
lowercased: String,
only_types: bool,
libs: bool,
exact: bool,
case_sensitive: bool,
limit: usize,
}
impl Query {
pub fn new(query: String) -> Query {
let lowercased = query.to_lowercase();
Query {
query,
lowercased,
only_types: false,
libs: false,
exact: false,
case_sensitive: false,
limit: usize::max_value(),
}
}
pub fn only_types(&mut self) {
self.only_types = true;
}
pub fn libs(&mut self) {
self.libs = true;
}
pub fn exact(&mut self) {
self.exact = true;
}
pub fn case_sensitive(&mut self) {
self.case_sensitive = true;
}
pub fn limit(&mut self, limit: usize) {
self.limit = limit
}
}
#[salsa::query_group(SymbolsDatabaseStorage)]
pub trait SymbolsDatabase: HirDatabase + SourceDatabaseExt + Upcast<dyn HirDatabase> {
/// The symbol index for a given module. These modules should only be in source roots that
/// are inside local_roots.
fn module_symbols(&self, module: Module) -> Arc<SymbolIndex>;
/// The symbol index for a given source root within library_roots.
fn library_symbols(&self, source_root_id: SourceRootId) -> Arc<SymbolIndex>;
/// The set of "local" (that is, from the current workspace) roots.
/// Files in local roots are assumed to change frequently.
#[salsa::input]
fn local_roots(&self) -> Arc<FxHashSet<SourceRootId>>;
/// The set of roots for crates.io libraries.
/// Files in libraries are assumed to never change.
#[salsa::input]
fn library_roots(&self) -> Arc<FxHashSet<SourceRootId>>;
}
fn library_symbols(db: &dyn SymbolsDatabase, source_root_id: SourceRootId) -> Arc<SymbolIndex> {
let _p = profile::span("library_symbols");
// todo: this could be parallelized, once I figure out how to do that...
let symbols = db
.source_root_crates(source_root_id)
.iter()
.flat_map(|&krate| Crate::from(krate).modules(db.upcast()))
// we specifically avoid calling SymbolsDatabase::module_symbols here, even they do the same thing,
// as the index for a library is not going to really ever change, and we do not want to store each
// module's index in salsa.
.flat_map(|module| SymbolCollector::collect(db.upcast(), module))
.collect();
Arc::new(SymbolIndex::new(symbols))
}
fn module_symbols(db: &dyn SymbolsDatabase, module: Module) -> Arc<SymbolIndex> {
let _p = profile::span("module_symbols");
let symbols = SymbolCollector::collect(db.upcast(), module);
Arc::new(SymbolIndex::new(symbols))
}
/// Need to wrap Snapshot to provide `Clone` impl for `map_with`
struct Snap<DB>(DB);
impl<DB: ParallelDatabase> Snap<salsa::Snapshot<DB>> {
fn new(db: &DB) -> Self {
Self(db.snapshot())
}
}
impl<DB: ParallelDatabase> Clone for Snap<salsa::Snapshot<DB>> {
fn clone(&self) -> Snap<salsa::Snapshot<DB>> {
Snap(self.0.snapshot())
}
}
impl<DB> std::ops::Deref for Snap<DB> {
type Target = DB;
fn deref(&self) -> &Self::Target {
&self.0
}
}
// Feature: Workspace Symbol
//
// Uses fuzzy-search to find types, modules and functions by name across your
// project and dependencies. This is **the** most useful feature, which improves code
// navigation tremendously. It mostly works on top of the built-in LSP
// functionality, however `#` and `*` symbols can be used to narrow down the
// search. Specifically,
//
// - `Foo` searches for `Foo` type in the current workspace
// - `foo#` searches for `foo` function in the current workspace
// - `Foo*` searches for `Foo` type among dependencies, including `stdlib`
// - `foo#*` searches for `foo` function among dependencies
//
// That is, `#` switches from "types" to all symbols, `*` switches from the current
// workspace to dependencies.
//
// Note that filtering does not currently work in VSCode due to the editor never
// sending the special symbols to the language server. Instead, you can configure
// the filtering via the `rust-analyzer.workspace.symbol.search.scope` and
// `rust-analyzer.workspace.symbol.search.kind` settings.
//
// |===
// | Editor | Shortcut
//
// | VS Code | kbd:[Ctrl+T]
// |===
pub fn world_symbols(db: &RootDatabase, query: Query) -> Vec<FileSymbol> {
let _p = profile::span("world_symbols").detail(|| query.query.clone());
let indices: Vec<_> = if query.libs {
db.library_roots()
.par_iter()
.map_with(Snap::new(db), |snap, &root| snap.library_symbols(root))
.collect()
} else {
let mut modules = Vec::new();
for &root in db.local_roots().iter() {
let crates = db.source_root_crates(root);
for &krate in crates.iter() {
modules.extend(Crate::from(krate).modules(db));
}
}
modules
.par_iter()
.map_with(Snap::new(db), |snap, &module| snap.module_symbols(module))
.collect()
};
query.search(&indices)
}
pub fn crate_symbols(db: &RootDatabase, krate: Crate, query: Query) -> Vec<FileSymbol> {
let _p = profile::span("crate_symbols").detail(|| format!("{query:?}"));
let modules = krate.modules(db);
let indices: Vec<_> = modules
.par_iter()
.map_with(Snap::new(db), |snap, &module| snap.module_symbols(module))
.collect();
query.search(&indices)
}
#[derive(Default)]
pub struct SymbolIndex {
symbols: Vec<FileSymbol>,
map: fst::Map<Vec<u8>>,
}
impl fmt::Debug for SymbolIndex {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("SymbolIndex").field("n_symbols", &self.symbols.len()).finish()
}
}
impl PartialEq for SymbolIndex {
fn eq(&self, other: &SymbolIndex) -> bool {
self.symbols == other.symbols
}
}
impl Eq for SymbolIndex {}
impl Hash for SymbolIndex {
fn hash<H: Hasher>(&self, hasher: &mut H) {
self.symbols.hash(hasher)
}
}
impl SymbolIndex {
fn new(mut symbols: Vec<FileSymbol>) -> SymbolIndex {
fn cmp(lhs: &FileSymbol, rhs: &FileSymbol) -> Ordering {
let lhs_chars = lhs.name.chars().map(|c| c.to_ascii_lowercase());
let rhs_chars = rhs.name.chars().map(|c| c.to_ascii_lowercase());
lhs_chars.cmp(rhs_chars)
}
symbols.par_sort_by(cmp);
let mut builder = fst::MapBuilder::memory();
let mut last_batch_start = 0;
for idx in 0..symbols.len() {
if let Some(next_symbol) = symbols.get(idx + 1) {
if cmp(&symbols[last_batch_start], next_symbol) == Ordering::Equal {
continue;
}
}
let start = last_batch_start;
let end = idx + 1;
last_batch_start = end;
let key = symbols[start].name.as_str().to_ascii_lowercase();
let value = SymbolIndex::range_to_map_value(start, end);
builder.insert(key, value).unwrap();
}
let map = fst::Map::new(builder.into_inner().unwrap()).unwrap();
SymbolIndex { symbols, map }
}
pub fn len(&self) -> usize {
self.symbols.len()
}
pub fn memory_size(&self) -> usize {
self.map.as_fst().size() + self.symbols.len() * mem::size_of::<FileSymbol>()
}
fn range_to_map_value(start: usize, end: usize) -> u64 {
debug_assert![start <= (std::u32::MAX as usize)];
debug_assert![end <= (std::u32::MAX as usize)];
((start as u64) << 32) | end as u64
}
fn map_value_to_range(value: u64) -> (usize, usize) {
let end = value as u32 as usize;
let start = (value >> 32) as usize;
(start, end)
}
}
impl Query {
pub(crate) fn search(self, indices: &[Arc<SymbolIndex>]) -> Vec<FileSymbol> {
let _p = profile::span("symbol_index::Query::search");
let mut op = fst::map::OpBuilder::new();
for file_symbols in indices.iter() {
let automaton = fst::automaton::Subsequence::new(&self.lowercased);
op = op.add(file_symbols.map.search(automaton))
}
let mut stream = op.union();
let mut res = Vec::new();
while let Some((_, indexed_values)) = stream.next() {
for indexed_value in indexed_values {
let symbol_index = &indices[indexed_value.index];
let (start, end) = SymbolIndex::map_value_to_range(indexed_value.value);
for symbol in &symbol_index.symbols[start..end] {
if self.only_types && !symbol.kind.is_type() {
continue;
}
if self.exact {
if symbol.name != self.query {
continue;
}
} else if self.case_sensitive
&& self.query.chars().any(|c| !symbol.name.contains(c))
{
continue;
}
res.push(symbol.clone());
if res.len() >= self.limit {
return res;
}
}
}
}
res
}
}
#[cfg(test)]
mod tests {
use base_db::fixture::WithFixture;
use expect_test::expect_file;
use hir::symbols::SymbolCollector;
use super::*;
#[test]
fn test_symbol_index_collection() {
let (db, _) = RootDatabase::with_many_files(
r#"
//- /main.rs
macro_rules! macro_rules_macro {
() => {}
};
macro_rules! define_struct {
() => {
struct StructFromMacro;
}
};
define_struct!();
macro Macro { }
struct Struct;
enum Enum {
A, B
}
union Union {}
impl Struct {
fn impl_fn() {}
}
trait Trait {
fn trait_fn(&self);
}
fn main() {
struct StructInFn;
}
const CONST: u32 = 1;
static STATIC: &'static str = "2";
type Alias = Struct;
mod a_mod {
struct StructInModA;
}
const _: () = {
struct StructInUnnamedConst;
()
};
const CONST_WITH_INNER: () = {
struct StructInNamedConst;
()
};
mod b_mod;
//- /b_mod.rs
struct StructInModB;
"#,
);
let symbols: Vec<_> = Crate::from(db.test_crate())
.modules(&db)
.into_iter()
.map(|module_id| {
let mut symbols = SymbolCollector::collect(&db, module_id);
symbols.sort_by_key(|it| it.name.clone());
(module_id, symbols)
})
.collect();
expect_file!["./test_data/test_symbol_index_collection.txt"].assert_debug_eq(&symbols);
}
}