Frame remove_all with size limit. (#9106)

* remove prefixed content with limit.

* test match

* factor comment and factor ext limit removal.

* fix benchmark

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

substrate/primitives/state-machine/src/basic.rs

@@ -216,13 +216,13 @@ impl Externalities for BasicExternalities {
 		(true, num_removed as u32)
 	}
 
-	fn clear_prefix(&mut self, prefix: &[u8]) {
+	fn clear_prefix(&mut self, prefix: &[u8], _limit: Option<u32>) -> (bool, u32) {
 		if is_child_storage_key(prefix) {
 			warn!(
 				target: "trie",
 				"Refuse to clear prefix that is part of child storage key via main storage"
 			);
-			return;
+			return (false, 0);
 		}
 
 		let to_remove = self.inner.top.range::<[u8], _>((Bound::Included(prefix), Bound::Unbounded))
@@ -231,16 +231,19 @@ impl Externalities for BasicExternalities {
 			.cloned()
 			.collect::<Vec<_>>();
 
+		let num_removed = to_remove.len();
 		for key in to_remove {
 			self.inner.top.remove(&key);
 		}
+		(true, num_removed as u32)
 	}
 
 	fn clear_child_prefix(
 		&mut self,
 		child_info: &ChildInfo,
 		prefix: &[u8],
-	) {
+		_limit: Option<u32>,
+	) -> (bool, u32) {
 		if let Some(child) = self.inner.children_default.get_mut(child_info.storage_key()) {
 			let to_remove = child.data.range::<[u8], _>((Bound::Included(prefix), Bound::Unbounded))
 				.map(|(k, _)| k)
@@ -248,9 +251,13 @@ impl Externalities for BasicExternalities {
 				.cloned()
 				.collect::<Vec<_>>();
 
+			let num_removed = to_remove.len();
 			for key in to_remove {
 				child.data.remove(&key);
 			}
+			(true, num_removed as u32)
+		} else {
+			(true, 0)
 		}
 	}