1 files changed, 200 insertions, 0 deletions

diff --git a/crates/ra_hir/src/nameres/lower.rs b/crates/ra_hir/src/nameres/lower.rs
new file mode 100644
index 000000000..dd3bf245f
--- /dev/null
+++ b/crates/ra_hir/src/nameres/lower.rs
@@ -0,0 +1,200 @@
+use std::sync::Arc;
+
+use ra_syntax::{
+    TextRange, SyntaxKind, AstNode,
+    ast::{self, ModuleItemOwner},
+};
+use ra_db::{FileId, SourceRootId};
+
+use crate::{
+    SourceItemId, SourceFileItemId, Path, ModuleSource, HirDatabase, Name, SourceFileItems,
+    HirFileId, MacroCallLoc, AsName,
+    module_tree::ModuleId
+};
+/// A set of items and imports declared inside a module, without relation to
+/// other modules.
+///
+/// This sits in-between raw syntax and name resolution and allows us to avoid
+/// recomputing name res: if two instance of `InputModuleItems` are the same, we
+/// can avoid redoing name resolution.
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct InputModuleItems {
+    pub(crate) items: Vec<ModuleItem>,
+    pub(super) imports: Vec<Import>,
+}
+
+impl InputModuleItems {
+    pub(crate) fn input_module_items_query(
+        db: &impl HirDatabase,
+        source_root_id: SourceRootId,
+        module_id: ModuleId,
+    ) -> Arc<InputModuleItems> {
+        let module_tree = db.module_tree(source_root_id);
+        let source = module_id.source(&module_tree);
+        let file_id = source.file_id;
+        let source = ModuleSource::from_source_item_id(db, source);
+        let file_items = db.file_items(file_id);
+        let fill = |acc: &mut InputModuleItems, items: &mut Iterator<Item = ast::ItemOrMacro>| {
+            for item in items {
+                match item {
+                    ast::ItemOrMacro::Item(it) => {
+                        acc.add_item(file_id, &file_items, it);
+                    }
+                    ast::ItemOrMacro::Macro(macro_call) => {
+                        let item_id = file_items.id_of_unchecked(macro_call.syntax());
+                        let loc = MacroCallLoc {
+                            source_root_id,
+                            module_id,
+                            source_item_id: SourceItemId {
+                                file_id,
+                                item_id: Some(item_id),
+                            },
+                        };
+                        let id = loc.id(db);
+                        let file_id = HirFileId::from(id);
+                        let file_items = db.file_items(file_id);
+                        //FIXME: expand recursively
+                        for item in db.hir_source_file(file_id).items() {
+                            acc.add_item(file_id, &file_items, item);
+                        }
+                    }
+                }
+            }
+        };
+
+        let mut res = InputModuleItems::default();
+        match source {
+            ModuleSource::SourceFile(it) => fill(&mut res, &mut it.items_with_macros()),
+            ModuleSource::Module(it) => {
+                if let Some(item_list) = it.item_list() {
+                    fill(&mut res, &mut item_list.items_with_macros())
+                }
+            }
+        };
+        Arc::new(res)
+    }
+
+    pub(crate) fn add_item(
+        &mut self,
+        file_id: HirFileId,
+        file_items: &SourceFileItems,
+        item: &ast::ModuleItem,
+    ) -> Option<()> {
+        match item.kind() {
+            ast::ModuleItemKind::StructDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::EnumDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::FnDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::TraitDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::TypeDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::ImplBlock(_) => {
+                // impls don't define items
+            }
+            ast::ModuleItemKind::UseItem(it) => self.add_use_item(file_items, it),
+            ast::ModuleItemKind::ExternCrateItem(_) => {
+                // TODO
+            }
+            ast::ModuleItemKind::ConstDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::StaticDef(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+            ast::ModuleItemKind::Module(it) => {
+                self.items.push(ModuleItem::new(file_id, file_items, it)?)
+            }
+        }
+        Some(())
+    }
+
+    fn add_use_item(&mut self, file_items: &SourceFileItems, item: &ast::UseItem) {
+        let file_item_id = file_items.id_of_unchecked(item.syntax());
+        let start_offset = item.syntax().range().start();
+        Path::expand_use_item(item, |path, range| {
+            let kind = match range {
+                None => ImportKind::Glob,
+                Some(range) => ImportKind::Named(NamedImport {
+                    file_item_id,
+                    relative_range: range - start_offset,
+                }),
+            };
+            self.imports.push(Import { kind, path })
+        })
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub(super) enum Vis {
+    // Priv,
+    Other,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub(crate) struct ModuleItem {
+    pub(crate) id: SourceItemId,
+    pub(crate) name: Name,
+    pub(super) kind: SyntaxKind,
+    pub(super) vis: Vis,
+}
+
+impl ModuleItem {
+    fn new(
+        file_id: HirFileId,
+        file_items: &SourceFileItems,
+        item: &impl ast::NameOwner,
+    ) -> Option<ModuleItem> {
+        let name = item.name()?.as_name();
+        let kind = item.syntax().kind();
+        let vis = Vis::Other;
+        let item_id = Some(file_items.id_of_unchecked(item.syntax()));
+        let id = SourceItemId { file_id, item_id };
+        let res = ModuleItem {
+            id,
+            name,
+            kind,
+            vis,
+        };
+        Some(res)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(super) struct Import {
+    pub(super) path: Path,
+    pub(super) kind: ImportKind,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct NamedImport {
+    pub file_item_id: SourceFileItemId,
+    pub relative_range: TextRange,
+}
+
+impl NamedImport {
+    // FIXME: this is only here for one use-case in completion. Seems like a
+    // pretty gross special case.
+    pub fn range(&self, db: &impl HirDatabase, file_id: FileId) -> TextRange {
+        let source_item_id = SourceItemId {
+            file_id: file_id.into(),
+            item_id: Some(self.file_item_id),
+        };
+        let syntax = db.file_item(source_item_id);
+        let offset = syntax.range().start();
+        self.relative_range + offset
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(super) enum ImportKind {
+    Glob,
+    Named(NamedImport),
+}