1 files changed, 110 insertions, 0 deletions

diff --git a/crates/ra_hir/src/code_model/src.rs b/crates/ra_hir/src/code_model/src.rs
new file mode 100644
index 000000000..5785d3b26
--- /dev/null
+++ b/crates/ra_hir/src/code_model/src.rs
@@ -0,0 +1,110 @@
+use ra_syntax::{TreeArc, ast};
+
+use crate::{
+    HirFileId, DefDatabase, AstDatabase, Module, ModuleSource,
+    StructField, Struct, Enum, Union, EnumVariant, Function, Static, Trait, Const, TypeAlias,
+    FieldSource, MacroDef, ids::AstItemDef,
+};
+
+pub struct Source<T> {
+    pub file_id: HirFileId,
+    pub ast: T,
+}
+
+pub trait HasSource {
+    type Ast;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<Self::Ast>;
+}
+
+/// NB: Module is !HasSource, because it has two source nodes at the same time:
+/// definition and declaration.
+impl Module {
+    /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
+    pub fn definition_source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<ModuleSource> {
+        let def_map = db.crate_def_map(self.krate);
+        let decl_id = def_map[self.module_id].declaration;
+        let file_id = def_map[self.module_id].definition;
+        let ast = ModuleSource::new(db, file_id, decl_id);
+        let file_id = file_id.map(HirFileId::from).unwrap_or_else(|| decl_id.unwrap().file_id());
+        Source { file_id, ast }
+    }
+
+    /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
+    /// `None` for the crate root.
+    pub fn declaration_source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> Option<Source<TreeArc<ast::Module>>> {
+        let def_map = db.crate_def_map(self.krate);
+        let decl = def_map[self.module_id].declaration?;
+        let ast = decl.to_node(db);
+        Some(Source { file_id: decl.file_id(), ast })
+    }
+}
+
+impl HasSource for StructField {
+    type Ast = FieldSource;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<FieldSource> {
+        self.source_impl(db)
+    }
+}
+impl HasSource for Struct {
+    type Ast = TreeArc<ast::StructDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::StructDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for Union {
+    type Ast = TreeArc<ast::StructDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::StructDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for Enum {
+    type Ast = TreeArc<ast::EnumDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::EnumDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for EnumVariant {
+    type Ast = TreeArc<ast::EnumVariant>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::EnumVariant>> {
+        self.source_impl(db)
+    }
+}
+impl HasSource for Function {
+    type Ast = TreeArc<ast::FnDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::FnDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for Const {
+    type Ast = TreeArc<ast::ConstDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::ConstDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for Static {
+    type Ast = TreeArc<ast::StaticDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::StaticDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for Trait {
+    type Ast = TreeArc<ast::TraitDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::TraitDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for TypeAlias {
+    type Ast = TreeArc<ast::TypeAliasDef>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::TypeAliasDef>> {
+        self.id.source(db)
+    }
+}
+impl HasSource for MacroDef {
+    type Ast = TreeArc<ast::MacroCall>;
+    fn source(self, db: &(impl DefDatabase + AstDatabase)) -> Source<TreeArc<ast::MacroCall>> {
+        Source { file_id: self.id.0.file_id(), ast: self.id.0.to_node(db) }
+    }
+}