Implement FromIterator<Root<A>> for RootedVec<JS<A>> (fixes #5117)

2 files changed, 14 insertions, 3 deletions

diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index b1dcbbce163..8e48de2c680 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -29,7 +29,7 @@
 //! The `no_jsmanaged_fields!()` macro adds an empty implementation of `JSTraceable` to
 //! a datatype.
 
-use dom::bindings::js::JS;
+use dom::bindings::js::{JS, Root};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::utils::{Reflectable, Reflector, WindowProxyHandler};
 use script_task::ScriptChan;
@@ -69,6 +69,7 @@ use std::collections::{HashMap, HashSet};
 use std::ffi::CString;
 use std::hash::{Hash, Hasher};
 use std::intrinsics::return_address;
+use std::iter::{FromIterator, IntoIterator};
 use std::mem;
 use std::ops::{Deref, DerefMut};
 use std::rc::Rc;
@@ -511,6 +512,17 @@ impl<T: JSTraceable + Reflectable> DerefMut for RootedVec<T> {
     }
 }
 
+impl<A: JSTraceable + Reflectable> FromIterator<Root<A>> for RootedVec<JS<A>> {
+    #[allow(moved_no_move)]
+    fn from_iter<T>(iterable: T) -> RootedVec<JS<A>> where T: IntoIterator<Item=Root<A>> {
+        let mut vec = RootedVec::new_with_destination_address(unsafe {
+            return_address() as *const libc::c_void
+        });
+        vec.extend(iterable.into_iter().map(|item| JS::from_rooted(&item)));
+        vec
+    }
+}
+
 /// SM Callback that traces the rooted traceables
 pub unsafe fn trace_traceables(tracer: *mut JSTracer) {
     ROOTED_TRACEABLES.with(|ref traceables| {
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index ac21c9eefc2..f46cbc0be11 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -1629,8 +1629,7 @@ impl Node {
             Node::adopt(node, &*parent.owner_doc());
         }
         // Step 2.
-        let mut removed_nodes = RootedVec::new();
-        removed_nodes.extend(parent.children().map(|child| JS::from_rooted(&child)));
+        let removed_nodes = parent.children().collect::<RootedVec<_>>();
         // Step 3.
         let mut added_nodes = RootedVec::new();
         let added_nodes = if let Some(node) = node.as_ref() {