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|
//! Name resolution algorithm. The end result of the algorithm is `ItemMap`: a
//! map with maps each module to it's scope: the set of items, visible in the
//! module. That is, we only resolve imports here, name resolution of item
//! bodies will be done in a separate step.
//!
//! Like Rustc, we use an interative per-crate algorithm: we start with scopes
//! containing only directly defined items, and then iteratively resolve
//! imports.
//!
//! To make this work nicely in the IDE scenarios, we place `InputModuleItems`
//! in between raw syntax and name resolution. `InputModuleItems` are computed
//! using only the module's syntax, and it is all directly defined items plus
//! imports. The plain is to make `InputModuleItems` independent of local
//! modifications (that is, typing inside a function shold not change IMIs),
//! such that the results of name resolution can be preserved unless the module
//! structure itself is modified.
use std::{
sync::Arc,
time::Instant,
};
use rustc_hash::FxHashMap;
use ra_syntax::{
SmolStr, SyntaxKind::{self, *},
ast::{self, ModuleItemOwner}
};
use crate::{
Cancelable,
loc2id::{DefId, DefLoc},
descriptors::{
Path, PathKind,
DescriptorDatabase,
module::{ModuleId, ModuleTree, ModuleSourceNode},
},
syntax_ptr::{LocalSyntaxPtr},
input::SourceRootId,
};
/// Item map is the result of the name resolution. Item map contains, for each
/// module, the set of visible items.
#[derive(Default, Debug, PartialEq, Eq)]
pub(crate) struct ItemMap {
pub(crate) per_module: FxHashMap<ModuleId, ModuleScope>,
}
#[derive(Debug, Default, PartialEq, Eq, Clone)]
pub(crate) struct ModuleScope {
pub(crate) items: FxHashMap<SmolStr, Resolution>,
}
/// A set of items and imports declared inside a module, without relation to
/// other modules.
///
/// This stands in-between raw syntax and name resolution and alow us to avoid
/// recomputing name res: if `InputModuleItems` are the same, we can avoid
/// running name resolution.
#[derive(Debug, Default, PartialEq, Eq)]
pub(crate) struct InputModuleItems {
items: Vec<ModuleItem>,
imports: Vec<Import>,
}
#[derive(Debug, Clone, PartialEq, Eq)]
struct Import {
path: Path,
kind: ImportKind,
}
#[derive(Debug, Clone, PartialEq, Eq)]
enum ImportKind {
Glob,
// TODO: make offset independent
Named(LocalSyntaxPtr),
}
pub(crate) fn input_module_items(
db: &impl DescriptorDatabase,
source_root: SourceRootId,
module_id: ModuleId,
) -> Cancelable<Arc<InputModuleItems>> {
let module_tree = db._module_tree(source_root)?;
let source = module_id.source(&module_tree);
let res = match source.resolve(db) {
ModuleSourceNode::SourceFile(it) => {
let items = it.borrowed().items();
InputModuleItems::new(items)
}
ModuleSourceNode::Module(it) => {
let items = it
.borrowed()
.item_list()
.into_iter()
.flat_map(|it| it.items());
InputModuleItems::new(items)
}
};
Ok(Arc::new(res))
}
pub(crate) fn item_map(
db: &impl DescriptorDatabase,
source_root: SourceRootId,
) -> Cancelable<Arc<ItemMap>> {
let start = Instant::now();
let module_tree = db._module_tree(source_root)?;
let input = module_tree
.modules()
.map(|id| {
let items = db._input_module_items(source_root, id)?;
Ok((id, items))
})
.collect::<Cancelable<FxHashMap<_, _>>>()?;
let mut resolver = Resolver {
db: db,
input: &input,
source_root,
module_tree,
result: ItemMap::default(),
};
resolver.resolve()?;
let res = resolver.result;
let elapsed = start.elapsed();
log::info!("item_map: {:?}", elapsed);
Ok(Arc::new(res))
}
/// Resolution is basically `DefId` atm, but it should account for stuff like
/// multiple namespaces, ambiguity and errors.
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct Resolution {
/// None for unresolved
pub(crate) def_id: Option<DefId>,
/// ident by whitch this is imported into local scope.
/// TODO: make this offset-independent.
pub(crate) import_name: Option<LocalSyntaxPtr>,
}
// #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
// enum Namespace {
// Types,
// Values,
// }
// #[derive(Debug)]
// struct PerNs<T> {
// types: Option<T>,
// values: Option<T>,
// }
#[derive(Debug, PartialEq, Eq)]
struct ModuleItem {
ptr: LocalSyntaxPtr,
name: SmolStr,
kind: SyntaxKind,
vis: Vis,
}
#[derive(Debug, PartialEq, Eq)]
enum Vis {
// Priv,
Other,
}
impl InputModuleItems {
fn new<'a>(items: impl Iterator<Item = ast::ModuleItem<'a>>) -> InputModuleItems {
let mut res = InputModuleItems::default();
for item in items {
res.add_item(item);
}
res
}
fn add_item(&mut self, item: ast::ModuleItem) -> Option<()> {
match item {
ast::ModuleItem::StructDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::EnumDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::FnDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::TraitDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::TypeDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::ImplItem(_) => {
// impls don't define items
}
ast::ModuleItem::UseItem(it) => self.add_use_item(it),
ast::ModuleItem::ExternCrateItem(_) => {
// TODO
}
ast::ModuleItem::ConstDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::StaticDef(it) => self.items.push(ModuleItem::new(it)?),
ast::ModuleItem::Module(it) => self.items.push(ModuleItem::new(it)?),
}
Some(())
}
fn add_use_item(&mut self, item: ast::UseItem) {
Path::expand_use_item(item, |path, ptr| {
let kind = match ptr {
None => ImportKind::Glob,
Some(ptr) => ImportKind::Named(ptr),
};
self.imports.push(Import { kind, path })
})
}
}
impl ModuleItem {
fn new<'a>(item: impl ast::NameOwner<'a>) -> Option<ModuleItem> {
let name = item.name()?.text();
let ptr = LocalSyntaxPtr::new(item.syntax());
let kind = item.syntax().kind();
let vis = Vis::Other;
let res = ModuleItem {
ptr,
name,
kind,
vis,
};
Some(res)
}
}
struct Resolver<'a, DB> {
db: &'a DB,
input: &'a FxHashMap<ModuleId, Arc<InputModuleItems>>,
source_root: SourceRootId,
module_tree: Arc<ModuleTree>,
result: ItemMap,
}
impl<'a, DB> Resolver<'a, DB>
where
DB: DescriptorDatabase,
{
fn resolve(&mut self) -> Cancelable<()> {
for (&module_id, items) in self.input.iter() {
self.populate_module(module_id, items)
}
for &module_id in self.input.keys() {
crate::db::check_canceled(self.db)?;
self.resolve_imports(module_id);
}
Ok(())
}
fn populate_module(&mut self, module_id: ModuleId, input: &InputModuleItems) {
let file_id = module_id.source(&self.module_tree).file_id();
let mut module_items = ModuleScope::default();
for import in input.imports.iter() {
if let Some(name) = import.path.segments.iter().last() {
if let ImportKind::Named(ptr) = import.kind {
module_items.items.insert(
name.clone(),
Resolution {
def_id: None,
import_name: Some(ptr),
},
);
}
}
}
for item in input.items.iter() {
if item.kind == MODULE {
// handle submodules separatelly
continue;
}
let ptr = item.ptr.into_global(file_id);
let def_loc = DefLoc::Item { ptr };
let def_id = self.db.id_maps().def_id(def_loc);
let resolution = Resolution {
def_id: Some(def_id),
import_name: None,
};
module_items.items.insert(item.name.clone(), resolution);
}
for (name, mod_id) in module_id.children(&self.module_tree) {
let def_loc = DefLoc::Module {
id: mod_id,
source_root: self.source_root,
};
let def_id = self.db.id_maps().def_id(def_loc);
let resolution = Resolution {
def_id: Some(def_id),
import_name: None,
};
module_items.items.insert(name, resolution);
}
self.result.per_module.insert(module_id, module_items);
}
fn resolve_imports(&mut self, module_id: ModuleId) {
for import in self.input[&module_id].imports.iter() {
self.resolve_import(module_id, import);
}
}
fn resolve_import(&mut self, module_id: ModuleId, import: &Import) {
let ptr = match import.kind {
ImportKind::Glob => return,
ImportKind::Named(ptr) => ptr,
};
let mut curr = match import.path.kind {
// TODO: handle extern crates
PathKind::Plain => return,
PathKind::Self_ => module_id,
PathKind::Super => {
match module_id.parent(&self.module_tree) {
Some(it) => it,
// TODO: error
None => return,
}
}
PathKind::Crate => module_id.crate_root(&self.module_tree),
};
for (i, name) in import.path.segments.iter().enumerate() {
let is_last = i == import.path.segments.len() - 1;
let def_id = match self.result.per_module[&curr].items.get(name) {
None => return,
Some(res) => match res.def_id {
Some(it) => it,
None => return,
},
};
if !is_last {
curr = match self.db.id_maps().def_loc(def_id) {
DefLoc::Module { id, .. } => id,
_ => return,
}
} else {
self.update(module_id, |items| {
let res = Resolution {
def_id: Some(def_id),
import_name: Some(ptr),
};
items.items.insert(name.clone(), res);
})
}
}
}
fn update(&mut self, module_id: ModuleId, f: impl FnOnce(&mut ModuleScope)) {
let module_items = self.result.per_module.get_mut(&module_id).unwrap();
f(module_items)
}
}
#[cfg(test)]
mod tests {
use crate::{
mock_analysis::analysis_and_position,
descriptors::{DescriptorDatabase, module::ModuleDescriptor},
input::FilesDatabase,
};
use super::*;
fn item_map(fixture: &str) -> (Arc<ItemMap>, ModuleId) {
let (analysis, pos) = analysis_and_position(fixture);
let db = analysis.imp.db;
let source_root = db.file_source_root(pos.file_id);
let descr = ModuleDescriptor::guess_from_position(&*db, pos)
.unwrap()
.unwrap();
let module_id = descr.module_id;
(db._item_map(source_root).unwrap(), module_id)
}
#[test]
fn test_item_map() {
let (item_map, module_id) = item_map(
"
//- /lib.rs
mod foo;
use crate::foo::bar::Baz;
<|>
//- /foo/mod.rs
pub mod bar;
//- /foo/bar.rs
pub struct Baz;
",
);
let name = SmolStr::from("Baz");
let resolution = &item_map.per_module[&module_id].items[&name];
assert!(resolution.def_id.is_some());
}
}
|