Add a extend_from_iter method to RelationShipSourceCollection

Author: Brezak

crates/bevy_ecs/src/relationship/related_methods.rs

@@ -160,19 +160,13 @@ impl<'w> EntityWorldMut<'w> {
                 let collection = target.collection_mut_risky();
                 collection.clear();
 
-                // TODO: Optimize with extend
-                for entity in entities_to_relate {
-                    collection.add(*entity);
-                }
+                collection.extend_from_iter(entities_to_relate.iter().copied());
             } else {
                 let mut empty =
                     <R::RelationshipTarget as RelationshipTarget>::Collection::with_capacity(
                         entities_to_relate.len(),
                     );
-                // TODO: Optimize with extend
-                for entity in entities_to_relate {
-                    empty.add(*entity);
-                }
+                empty.extend_from_iter(entities_to_relate.iter().copied());
 
                 // SAFETY: We've just initialized this collection
                 self.insert_with_relationship_insert_hook_mode(

crates/bevy_ecs/src/relationship/relationship_source_collection.rs

@@ -46,6 +46,17 @@ pub trait RelationshipSourceCollection {
     fn is_empty(&self) -> bool {
         self.len() == 0
     }
+
+    /// Add multiple entities to collection at once.
+    ///
+    /// May be faster than repeatedly calling [`Self::add`].
+    fn extend_from_iter(&mut self, entities: impl IntoIterator<Item = Entity>) {
+        // The method name shouldn't conflict with `Extend::extend` as it's in the rust prelude and
+        // would always conflict with it.
+        for entity in entities {
+            self.add(entity);
+        }
+    }
 }
 
 impl RelationshipSourceCollection for Vec<Entity> {
@@ -82,6 +93,10 @@ impl RelationshipSourceCollection for Vec<Entity> {
     fn clear(&mut self) {
         self.clear();
     }
+
+    fn extend_from_iter(&mut self, entities: impl IntoIterator<Item = Entity>) {
+        self.extend(entities);
+    }
 }
 
 impl RelationshipSourceCollection for EntityHashSet {
@@ -112,6 +127,10 @@ impl RelationshipSourceCollection for EntityHashSet {
     fn clear(&mut self) {
         self.0.clear();
     }
+
+    fn extend_from_iter(&mut self, entities: impl IntoIterator<Item = Entity>) {
+        self.extend(entities);
+    }
 }
 
 impl<const N: usize> RelationshipSourceCollection for SmallVec<[Entity; N]> {
@@ -148,6 +167,10 @@ impl<const N: usize> RelationshipSourceCollection for SmallVec<[Entity; N]> {
     fn clear(&mut self) {
         self.clear();
     }
+
+    fn extend_from_iter(&mut self, entities: impl IntoIterator<Item = Entity>) {
+        self.extend(entities);
+    }
 }
 
 impl RelationshipSourceCollection for Entity {
@@ -187,6 +210,12 @@ impl RelationshipSourceCollection for Entity {
     fn clear(&mut self) {
         *self = Entity::PLACEHOLDER;
     }
+
+    fn extend_from_iter(&mut self, entities: impl IntoIterator<Item = Entity>) {
+        if let Some(entity) = entities.into_iter().last() {
+            *self = entity;
+        }
+    }
 }
 
 #[cfg(test)]