1 files changed, 453 insertions, 0 deletions

diff --git a/crates/ra_analysis/src/descriptors/module/nameres.rs b/crates/ra_analysis/src/descriptors/module/nameres.rs
new file mode 100644
index 000000000..c5bf467ca
--- /dev/null
+++ b/crates/ra_analysis/src/descriptors/module/nameres.rs
@@ -0,0 +1,453 @@
+//! Name resolution algorithm
+use std::{
+    sync::Arc,
+    time::Instant,
+};
+
+use rustc_hash::FxHashMap;
+
+use ra_syntax::{
+    SmolStr, SyntaxKind::{self, *},
+    ast::{self, AstNode, ModuleItemOwner}
+};
+
+use crate::{
+    Cancelable,
+    loc2id::{DefId, DefLoc},
+    descriptors::{
+        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>,
+    pub(crate) import_resolutions: FxHashMap<LocalSyntaxPtr, DefId>,
+}
+
+/// 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>,
+    glob_imports: Vec<Path>,
+    imports: Vec<Path>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct Path {
+    kind: PathKind,
+    segments: Vec<(LocalSyntaxPtr, SmolStr)>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum PathKind {
+    Abs,
+    Self_,
+    Super,
+    Crate,
+}
+
+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) {
+        if let Some(tree) = item.use_tree() {
+            self.add_use_tree(None, tree);
+        }
+    }
+
+    fn add_use_tree(&mut self, prefix: Option<Path>, tree: ast::UseTree) {
+        if let Some(use_tree_list) = tree.use_tree_list() {
+            let prefix = match tree.path() {
+                None => prefix,
+                Some(path) => match convert_path(prefix, path) {
+                    Some(it) => Some(it),
+                    None => return, // TODO: report errors somewhere
+                },
+            };
+            for tree in use_tree_list.use_trees() {
+                self.add_use_tree(prefix.clone(), tree);
+            }
+        } else {
+            if let Some(path) = tree.path() {
+                if let Some(path) = convert_path(prefix, path) {
+                    if tree.has_star() {
+                        &mut self.glob_imports
+                    } else {
+                        &mut self.imports
+                    }
+                    .push(path);
+                }
+            }
+        }
+    }
+}
+
+fn convert_path(prefix: Option<Path>, path: ast::Path) -> Option<Path> {
+    let prefix = if let Some(qual) = path.qualifier() {
+        Some(convert_path(prefix, qual)?)
+    } else {
+        None
+    };
+    let segment = path.segment()?;
+    let res = match segment.kind()? {
+        ast::PathSegmentKind::Name(name) => {
+            let mut res = prefix.unwrap_or_else(|| Path {
+                kind: PathKind::Abs,
+                segments: Vec::with_capacity(1),
+            });
+            let ptr = LocalSyntaxPtr::new(name.syntax());
+            res.segments.push((ptr, name.text()));
+            res
+        }
+        ast::PathSegmentKind::CrateKw => {
+            if prefix.is_some() {
+                return None;
+            }
+            Path {
+                kind: PathKind::Crate,
+                segments: Vec::new(),
+            }
+        }
+        ast::PathSegmentKind::SelfKw => {
+            if prefix.is_some() {
+                return None;
+            }
+            Path {
+                kind: PathKind::Self_,
+                segments: Vec::new(),
+            }
+        }
+        ast::PathSegmentKind::SuperKw => {
+            if prefix.is_some() {
+                return None;
+            }
+            Path {
+                kind: PathKind::Super,
+                segments: Vec::new(),
+            }
+        }
+    };
+    Some(res)
+}
+
+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((ptr, name)) = import.segments.last() {
+                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: &Path) {
+        let mut curr = match import.kind {
+            // TODO: handle extern crates
+            PathKind::Abs => 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, (ptr, name)) in import.segments.iter().enumerate() {
+            let is_last = i == import.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,
+                },
+            };
+
+            self.update(module_id, |items| {
+                items.import_resolutions.insert(*ptr, def_id);
+            });
+
+            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());
+    }
+}