Make dictionaries contain Root<T> values instead of JS<T>, ensuring that they will not be collected while the dictionary is alive.

src/components/script/dom/bindings/codegen/CodegenRust.py

@@ -602,6 +602,8 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
                                           failureCode)
             return handleOptional(template, declType, isOptional)
 
+        descriptorType = descriptor.memberType if isMember else descriptor.nativeType
+
         templateBody = ""
         if descriptor.interface.isConsequential():
             raise TypeError("Consequential interface %s being used as an "
@@ -617,11 +619,14 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
                     descriptor,
                     "(${val}).to_object()"))
 
-        declType = CGGeneric(descriptor.nativeType)
+        declType = CGGeneric(descriptorType)
         if type.nullable():
             templateBody = "Some(%s)" % templateBody
             declType = CGWrapper(declType, pre="Option<", post=">")
 
+        if isMember:
+            templateBody += ".root()"
+
         templateBody = wrapObjectTemplate(templateBody, isDefinitelyObject,
                                           type, failureCode)
 
@@ -4069,7 +4074,7 @@ class CGDictionary(CGThing):
     def struct(self):
         d = self.dictionary
         if d.parent:
-            inheritance = "  pub parent: %s::%s,\n" % (self.makeModuleName(d.parent),
+            inheritance = "  pub parent: %s::%s<'a, 'b>,\n" % (self.makeModuleName(d.parent),
                                                    self.makeClassName(d.parent))
         else:
             inheritance = ""
@@ -4078,7 +4083,7 @@ class CGDictionary(CGThing):
                        for m in self.memberInfo]
 
         return (string.Template(
-                "pub struct ${selfName} {\n" +
+                "pub struct ${selfName}<'a, 'b> {\n" +
                 "${inheritance}" +
                 "\n".join(memberDecls) + "\n" +
                 "}").substitute( { "selfName": self.makeClassName(d),
@@ -4104,7 +4109,7 @@ class CGDictionary(CGThing):
         memberInits = CGList([memberInit(m) for m in self.memberInfo])
 
         return string.Template(
-            "impl ${selfName} {\n"
+            "impl<'a, 'b> ${selfName}<'a, 'b> {\n"
             "  pub fn new(cx: *JSContext, val: JSVal) -> Result<${selfName}, ()> {\n"
             "    let object = if val.is_null_or_undefined() {\n"
             "        ptr::null()\n"
@@ -4305,7 +4310,7 @@ class CGBindingRoot(CGThing):
             'js::glue::{RUST_JS_NumberValue, RUST_JSID_IS_STRING}',
             'dom::types::*',
             'dom::bindings',
-            'dom::bindings::js::{JS, JSRef, RootedReference, Temporary, OptionalRootable, OptionalRootedRootable}',
+            'dom::bindings::js::{JS, JSRef, Root, RootedReference, Temporary, OptionalRootable, OptionalRootedRootable, ResultRootable}',
             'dom::bindings::utils::{CreateDOMGlobal, CreateInterfaceObjects2}',
             'dom::bindings::utils::{ConstantSpec, cx_for_dom_object, Default}',
             'dom::bindings::utils::{dom_object_slot, DOM_OBJECT_SLOT, DOMClass}',

src/components/script/dom/bindings/codegen/Configuration.py

@@ -135,6 +135,7 @@ class Descriptor(DescriptorProvider):
 
         self.returnType = "Temporary<%s>" % ifaceName
         self.argumentType = "JSRef<%s>" % ifaceName
+        self.memberType = "Root<'a, 'b, %s>" % ifaceName
         self.nativeType = desc.get('nativeType', nativeTypeDefault)
         self.concreteType = desc.get('concreteType', ifaceName)
         self.createGlobal = desc.get('createGlobal', False)

src/components/script/dom/bindings/js.rs

@@ -284,6 +284,12 @@ impl<T: Reflectable, U> ResultRootable<T, U> for Result<Temporary<T>, U> {
     }
 }
 
+impl<T: Reflectable, U> ResultRootable<T, U> for Result<JS<T>, U> {
+    fn root<'a, 'b>(self) -> Result<Root<'a, 'b, T>, U> {
+        self.map(|inner| inner.root())
+    }
+}
+
 /// Provides a facility to push unrooted values onto lists of rooted values. This is safe
 /// under the assumption that said lists are reachable via the GC graph, and therefore the
 /// new values are transitively rooted for the lifetime of their new owner.

src/components/script/dom/mouseevent.rs

@@ -61,13 +61,11 @@ impl MouseEvent {
                        type_: DOMString,
                        init: &MouseEventBinding::MouseEventInit) -> Fallible<Temporary<MouseEvent>> {
         let mut ev = MouseEvent::new(owner).root();
-        let view = init.view.as_ref().map(|view| view.root());
+        ev.InitMouseEvent(type_, init.bubbles, init.cancelable, init.view.root_ref(),
-        let related_target = init.relatedTarget.as_ref().map(|relatedTarget| relatedTarget.root());
-        ev.InitMouseEvent(type_, init.bubbles, init.cancelable, view.root_ref(),
                           init.detail, init.screenX, init.screenY,
                           init.clientX, init.clientY, init.ctrlKey,
                           init.altKey, init.shiftKey, init.metaKey,
-                          init.button, related_target.root_ref());
+                          init.button, init.relatedTarget.root_ref());
         Ok(Temporary::from_rooted(&*ev))
     }
 }

src/components/script/dom/uievent.rs

@@ -46,9 +46,8 @@ impl UIEvent {
                        type_: DOMString,
                        init: &UIEventBinding::UIEventInit) -> Fallible<Temporary<UIEvent>> {
         let mut ev = UIEvent::new(owner).root();
-        let view = init.view.as_ref().map(|view| view.root());
         ev.InitUIEvent(type_, init.parent.bubbles, init.parent.cancelable,
-                       view.root_ref(), init.detail);
+                       init.view.root_ref(), init.detail);
         Ok(Temporary::from_rooted(&*ev))
     }
 }