Bug 1334051 - Part 2: Invoke attributeChangedCallback only if attribute name is in the observed attribute list.

We call attributeChangedCallback in two cases:

1. When any of the attributes in the observed attribute list has changed, appended, removed, or replaced.

2. When upgrading an element, for each attribute in element's attribute list that is in the observed attribute list.

Note: w/ Fixup for not implementing an API Enhancement Bug 1363481.

Tag UXP Issue #1344

1 files changed, 108 insertions, 11 deletions

diff --git a/dom/base/CustomElementRegistry.cpp b/dom/base/CustomElementRegistry.cpp
index cc6264b03..34ad9549d 100644
--- a/dom/base/CustomElementRegistry.cpp
+++ b/dom/base/CustomElementRegistry.cpp
@@ -434,8 +434,27 @@ CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType
                                                 LifecycleCallbackArgs* aArgs,
                                                 CustomElementDefinition* aDefinition)
 {
+  RefPtr<CustomElementData> elementData = aCustomElement->GetCustomElementData();
+  MOZ_ASSERT(elementData, "CustomElementData should exist");
+
+  // Let DEFINITION be ELEMENT's definition
+  CustomElementDefinition* definition = aDefinition;
+  if (!definition) {
+    mozilla::dom::NodeInfo* info = aCustomElement->NodeInfo();
+
+    // Make sure we get the correct definition in case the element
+    // is a extended custom element e.g. <button is="x-button">.
+    nsCOMPtr<nsIAtom> typeAtom = elementData ?
+      elementData->mType.get() : info->NameAtom();
+
+    definition = mCustomDefinitions.Get(typeAtom);
+    if (!definition || definition->mLocalName != info->NameAtom()) {
+      return;
+    }
+  }
+
   auto callback =
-    CreateCustomElementCallback(aType, aCustomElement, aArgs, aDefinition);
+    CreateCustomElementCallback(aType, aCustomElement, aArgs, definition);
   if (!callback) {
     return;
   }
@@ -445,9 +464,17 @@ CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType
     return;
   }
 
+  if (aType == nsIDocument::eAttributeChanged) {
+    nsCOMPtr<nsIAtom> attrName = NS_Atomize(aArgs->name);
+    if (definition->mObservedAttributes.IsEmpty() ||
+        !definition->mObservedAttributes.Contains(attrName)) {
+      return;
+    }
+  }
+
   CustomElementReactionsStack* reactionsStack =
     docGroup->CustomElementReactionsStack();
-  reactionsStack->EnqueueCallbackReaction(this, aCustomElement, aDefinition,
+  reactionsStack->EnqueueCallbackReaction(this, aCustomElement, definition,
                                           Move(callback));
 }
 
@@ -657,6 +684,7 @@ CustomElementRegistry::Define(const nsAString& aName,
 
   JS::Rooted<JSObject*> constructorPrototype(cx);
   nsAutoPtr<LifecycleCallbacks> callbacksHolder(new LifecycleCallbacks());
+  nsCOMArray<nsIAtom> observedAttributes;
   { // Set mIsCustomDefinitionRunning.
     /**
      * 9. Set this CustomElementRegistry's element definition is running flag.
@@ -718,6 +746,14 @@ CustomElementRegistry::Define(const nsAString& aName,
         return;
       }
 
+      // Note: We call the init from the constructorProtoUnwrapped's compartment
+      //       here.
+      JS::RootedValue rootedv(cx, JS::ObjectValue(*constructorProtoUnwrapped));
+      if (!JS_WrapValue(cx, &rootedv) || !callbacksHolder->Init(cx, rootedv)) {
+        aRv.StealExceptionFromJSContext(cx);
+        return;
+      }
+
       /**
        * 10.5. Let observedAttributes be an empty sequence<DOMString>.
        * 10.6. If the value of the entry in lifecycleCallbacks with key
@@ -730,14 +766,45 @@ CustomElementRegistry::Define(const nsAString& aName,
        *          any exceptions from the conversion.
        */
       // TODO: Bug 1293921 - Implement connected/disconnected/adopted/attributeChanged lifecycle callbacks for custom elements
+      if (callbacksHolder->mAttributeChangedCallback.WasPassed()) {
+        // Enter constructor's compartment.
+        JSAutoCompartment ac(cx, constructor);
+        JS::Rooted<JS::Value> observedAttributesIterable(cx);
+
+        if (!JS_GetProperty(cx, constructor, "observedAttributes",
+                            &observedAttributesIterable)) {
+          aRv.StealExceptionFromJSContext(cx);
+          return;
+        }
 
-      // Note: We call the init from the constructorProtoUnwrapped's compartment
-      //       here.
-      JS::RootedValue rootedv(cx, JS::ObjectValue(*constructorProtoUnwrapped));
-      if (!JS_WrapValue(cx, &rootedv) || !callbacksHolder->Init(cx, rootedv)) {
-        aRv.StealExceptionFromJSContext(cx);
-        return;
-      }
+        if (!observedAttributesIterable.isUndefined()) {
+          JS::ForOfIterator iter(cx);
+          if (!iter.init(observedAttributesIterable)) {
+            aRv.StealExceptionFromJSContext(cx);
+            return;
+          }
+
+          JS::Rooted<JS::Value> attribute(cx);
+          while (true) {
+            bool done;
+            if (!iter.next(&attribute, &done)) {
+              aRv.StealExceptionFromJSContext(cx);
+              return;
+            }
+            if (done) {
+              break;
+            }
+
+            JSString *attrJSStr = attribute.toString();
+            nsAutoJSString attrStr;
+            if (!attrStr.init(cx, attrJSStr)) {
+              aRv.StealExceptionFromJSContext(cx);
+              return;
+            }
+            observedAttributes.AppendElement(NS_Atomize(attrStr));
+          }
+        }
+      } // Leave constructor's compartment.
     } // Leave constructorProtoUnwrapped's compartment.
   } // Unset mIsCustomDefinitionRunning
 
@@ -754,6 +821,7 @@ CustomElementRegistry::Define(const nsAString& aName,
     new CustomElementDefinition(nameAtom,
                                 localNameAtom,
                                 &aFunctionConstructor,
+                                Move(observedAttributes),
                                 constructorPrototype,
                                 callbacks,
                                 0 /* TODO dependent on HTML imports. Bug 877072 */);
@@ -878,8 +946,35 @@ CustomElementRegistry::Upgrade(Element* aElement,
     return;
   }
 
-  // Step 3 and Step 4.
-  // TODO: Bug 1334051 - Implement list of observed attributes for custom elements' attributeChanged callbacks
+  // Step 3.
+  if (!aDefinition->mObservedAttributes.IsEmpty()) {
+    uint32_t count = aElement->GetAttrCount();
+    for (uint32_t i = 0; i < count; i++) {
+      mozilla::dom::BorrowedAttrInfo info = aElement->GetAttrInfoAt(i);
+
+      const nsAttrName* name = info.mName;
+      nsIAtom* attrName = name->LocalName();
+
+      if (aDefinition->IsInObservedAttributeList(attrName)) {
+        int32_t namespaceID = name->NamespaceID();
+        nsAutoString attrValue, namespaceURI;
+        info.mValue->ToString(attrValue);
+        nsContentUtils::NameSpaceManager()->GetNameSpaceURI(namespaceID,
+                                                            namespaceURI);
+
+        LifecycleCallbackArgs args = {
+          nsDependentAtomString(attrName),
+          NullString(),
+          (attrValue.IsEmpty() ? NullString() : attrValue),
+          (namespaceURI.IsEmpty() ? NullString() : namespaceURI)
+        };
+        EnqueueLifecycleCallback(nsIDocument::eAttributeChanged, aElement,
+                                 &args, aDefinition);
+      }
+    }
+  }
+
+  // Step 4.
   // TODO: Bug 1334043 - Implement connected lifecycle callbacks for custom elements
 
   // Step 5.
@@ -1051,12 +1146,14 @@ CustomElementReactionsStack::InvokeReactions(ElementQueue* aElementQueue,
 CustomElementDefinition::CustomElementDefinition(nsIAtom* aType,
                                                  nsIAtom* aLocalName,
                                                  Function* aConstructor,
+                                                 nsCOMArray<nsIAtom>&& aObservedAttributes,
                                                  JSObject* aPrototype,
                                                  LifecycleCallbacks* aCallbacks,
                                                  uint32_t aDocOrder)
   : mType(aType),
     mLocalName(aLocalName),
     mConstructor(new CustomElementConstructor(aConstructor)),
+    mObservedAttributes(Move(aObservedAttributes)),
     mPrototype(aPrototype),
     mCallbacks(aCallbacks),
     mDocOrder(aDocOrder)