Support native promise callbacks.

components/script/dom/promisenativehandler.rs

@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use dom::bindings::codegen::Bindings::PromiseNativeHandlerBinding;
+use dom::bindings::global::GlobalRef;
+use dom::bindings::js::Root;
+use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::bindings::trace::JSTraceable;
+use heapsize::HeapSizeOf;
+use js::jsapi::{JSContext, HandleValue};
+
+pub trait Callback: JSTraceable + HeapSizeOf {
+    fn callback(&self, cx: *mut JSContext, v: HandleValue);
+}
+
+#[dom_struct]
+pub struct PromiseNativeHandler {
+    reflector: Reflector,
+    resolve: Option<Box<Callback>>,
+    reject: Option<Box<Callback>>,
+}
+
+impl PromiseNativeHandler {
+    pub fn new(global: GlobalRef,
+               resolve: Option<Box<Callback>>,
+               reject: Option<Box<Callback>>)
+               -> Root<PromiseNativeHandler> {
+        reflect_dom_object(box PromiseNativeHandler {
+            reflector: Reflector::new(),
+            resolve: resolve,
+            reject: reject,
+        }, global, PromiseNativeHandlerBinding::Wrap)
+    }
+
+    fn callback(callback: &Option<Box<Callback>>, cx: *mut JSContext, v: HandleValue) {
+        if let Some(ref callback) = *callback {
+            callback.callback(cx, v)
+        }
+    }
+
+    pub fn resolved_callback(&self, cx: *mut JSContext, v: HandleValue) {
+        PromiseNativeHandler::callback(&self.resolve, cx, v)
+    }
+
+    pub fn rejected_callback(&self, cx: *mut JSContext, v: HandleValue) {
+        PromiseNativeHandler::callback(&self.reject, cx, v)
+    }
+}