Implement ancestors_with_macros in a better way

Author: flodiebold

crates/ra_hir/src/source_binder.rs

@@ -76,7 +76,7 @@ fn def_with_body_from_child_node(
     db: &impl HirDatabase,
     child: InFile<&SyntaxNode>,
 ) -> Option<DefWithBody> {
-    ancestors_with_macros(db, child).find_map(|node| {
+    child.cloned().ancestors_with_macros(db).find_map(|node| {
         let n = &node.value;
         match_ast! {
             match n {
@@ -89,17 +89,6 @@ fn def_with_body_from_child_node(
     })
 }
 
-fn ancestors_with_macros<'a>(
-    db: &'a (impl HirDatabase),
-    node: InFile<&SyntaxNode>,
-) -> impl Iterator<Item = InFile<SyntaxNode>> + 'a {
-    let file = node.with_value(()); // keep just the file id for borrow checker purposes
-    let parent_node = node.file_id.call_node(db);
-    let parent_ancestors: Box<dyn Iterator<Item = InFile<SyntaxNode>>> =
-        Box::new(parent_node.into_iter().flat_map(move |n| ancestors_with_macros(db, n.as_ref())));
-    node.value.ancestors().map(move |n| file.with_value(n)).chain(parent_ancestors)
-}
-
 /// `SourceAnalyzer` is a convenience wrapper which exposes HIR API in terms of
 /// original source files. It should not be used inside the HIR itself.
 #[derive(Debug)]

crates/ra_hir_expand/src/lib.rs

@@ -301,3 +301,40 @@ impl<T> InFile<T> {
         db.parse_or_expand(self.file_id).expect("source created from invalid file")
     }
 }
+
+impl<T: Clone> InFile<&T> {
+    pub fn cloned(&self) -> InFile<T> {
+        self.with_value(self.value.clone())
+    }
+}
+
+impl InFile<SyntaxNode> {
+    pub fn ancestors_with_macros<'a>(
+        self,
+        db: &'a impl crate::db::AstDatabase,
+    ) -> impl Iterator<Item = InFile<SyntaxNode>> + 'a {
+        SyntaxNodeAncestorsWithMacros { db, node: Some(self) }
+    }
+}
+
+pub struct SyntaxNodeAncestorsWithMacros<'a, D: crate::db::AstDatabase> {
+    db: &'a D,
+    node: Option<InFile<SyntaxNode>>,
+}
+
+impl<'a, D: crate::db::AstDatabase> Iterator for SyntaxNodeAncestorsWithMacros<'a, D> {
+    type Item = InFile<SyntaxNode>;
+    fn next(&mut self) -> Option<Self::Item> {
+        let node = self.node.take()?;
+        match node.value.parent() {
+            Some(parent) => {
+                self.node = Some(node.with_value(parent));
+            }
+            None => {
+                let parent_node = node.file_id.call_node(self.db)?;
+                self.node = Some(parent_node);
+            }
+        }
+        Some(node)
+    }
+}