Bug 1315885 - Part 4: Implement callback reaction for custom element reactions.

Note: Skipped SyncInvokeReactions since it is removed in CE v1, waste of time.

Tag UXP Issue #1344

4 files changed, 101 insertions, 136 deletions

diff --git a/dom/base/CustomElementRegistry.cpp b/dom/base/CustomElementRegistry.cpp
index 6419c1425..bd26e4ff3 100644
--- a/dom/base/CustomElementRegistry.cpp
+++ b/dom/base/CustomElementRegistry.cpp
@@ -92,26 +92,12 @@ CustomElementData::CustomElementData(nsIAtom* aType)
 
 CustomElementData::CustomElementData(nsIAtom* aType, State aState)
   : mType(aType)
-  , mCurrentCallback(-1)
   , mElementIsBeingCreated(false)
   , mCreatedCallbackInvoked(true)
-  , mAssociatedMicroTask(-1)
   , mState(aState)
 {
 }
 
-void
-CustomElementData::RunCallbackQueue()
-{
-  // Note: It's possible to re-enter this method.
-  while (static_cast<uint32_t>(++mCurrentCallback) < mCallbackQueue.Length()) {
-    mCallbackQueue[mCurrentCallback]->Call();
-  }
-
-  mCallbackQueue.Clear();
-  mCurrentCallback = -1;
-}
-
 //-----------------------------------------------------
 // CustomElementRegistry
 
@@ -128,7 +114,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CustomElementRegistry)
   for (auto iter = tmp->mCustomDefinitions.Iter(); !iter.Done(); iter.Next()) {
-    nsAutoPtr<LifecycleCallbacks>& callbacks = iter.UserData()->mCallbacks;
+    auto& callbacks = iter.UserData()->mCallbacks;
 
     if (callbacks->mAttributeChangedCallback.WasPassed()) {
       NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb,
@@ -191,43 +177,6 @@ CustomElementRegistry::IsCustomElementEnabled(JSContext* aCx, JSObject* aObject)
          nsContentUtils::IsWebComponentsEnabled();
 }
 
-/* static */ void
-CustomElementRegistry::ProcessTopElementQueue()
-{
-  MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
-
-  nsTArray<RefPtr<CustomElementData>>& stack = *sProcessingStack;
-  uint32_t firstQueue = stack.LastIndexOf((CustomElementData*) nullptr);
-
-  for (uint32_t i = firstQueue + 1; i < stack.Length(); ++i) {
-    // Callback queue may have already been processed in an earlier
-    // element queue or in an element queue that was popped
-    // off more recently.
-    if (stack[i]->mAssociatedMicroTask != -1) {
-      stack[i]->RunCallbackQueue();
-      stack[i]->mAssociatedMicroTask = -1;
-    }
-  }
-
-  // If this was actually the base element queue, don't bother trying to pop
-  // the first "queue" marker (sentinel).
-  if (firstQueue != 0) {
-    stack.SetLength(firstQueue);
-  } else {
-    // Don't pop sentinel for base element queue.
-    stack.SetLength(1);
-  }
-}
-
-/* static */ void
-CustomElementRegistry::XPCOMShutdown()
-{
-  sProcessingStack.reset();
-}
-
-/* static */ Maybe<nsTArray<RefPtr<CustomElementData>>>
-CustomElementRegistry::sProcessingStack;
-
 CustomElementRegistry::CustomElementRegistry(nsPIDOMWindowInner* aWindow)
  : mWindow(aWindow)
  , mIsCustomDefinitionRunning(false)
@@ -237,12 +186,6 @@ CustomElementRegistry::CustomElementRegistry(nsPIDOMWindowInner* aWindow)
   MOZ_ALWAYS_TRUE(mConstructors.init());
 
   mozilla::HoldJSObjects(this);
-
-  if (!sProcessingStack) {
-    sProcessingStack.emplace();
-    // Add the base queue sentinel to the processing stack.
-    sProcessingStack->AppendElement((CustomElementData*) nullptr);
-  }
 }
 
 CustomElementRegistry::~CustomElementRegistry()
@@ -346,14 +289,15 @@ CustomElementRegistry::SetupCustomElement(Element* aElement,
 
   // Enqueuing the created callback will set the CustomElementData on the
   // element, causing prototype swizzling to occur in Element::WrapObject.
-  EnqueueLifecycleCallback(nsIDocument::eCreated, aElement, nullptr, definition);
+  // We make it synchronously for createElement/createElementNS in order to
+  // pass tests. It'll be removed when we deprecate custom elements v0.
+  // SyncInvokeReactions(nsIDocument::eCreated, aElement, definition);
 }
 
-void
-CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType aType,
-                                                Element* aCustomElement,
-                                                LifecycleCallbackArgs* aArgs,
-                                                CustomElementDefinition* aDefinition)
+UniquePtr<CustomElementCallback>
+CustomElementRegistry::CreateCustomElementCallback(
+  nsIDocument::ElementCallbackType aType, Element* aCustomElement,
+  LifecycleCallbackArgs* aArgs, CustomElementDefinition* aDefinition)
 {
   RefPtr<CustomElementData> elementData = aCustomElement->GetCustomElementData();
   MOZ_ASSERT(elementData, "CustomElementData should exist");
@@ -372,7 +316,7 @@ CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType
     if (!definition || definition->mLocalName != info->NameAtom()) {
       // Trying to enqueue a callback for an element that is not
       // a custom element. We are done, nothing to do.
-      return;
+      return nullptr;
     }
   }
 
@@ -406,7 +350,7 @@ CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType
 
   // If there is no such callback, stop.
   if (!func) {
-    return;
+    return nullptr;
   }
 
   if (aType == nsIDocument::eCreated) {
@@ -414,54 +358,41 @@ CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType
   } else if (!elementData->mCreatedCallbackInvoked) {
     // Callbacks other than created callback must not be enqueued
     // until after the created callback has been invoked.
-    return;
+    return nullptr;
   }
 
   // Add CALLBACK to ELEMENT's callback queue.
-  CustomElementCallback* callback = new CustomElementCallback(aCustomElement,
-                                                              aType,
-                                                              func,
-                                                              elementData);
-  // Ownership of callback is taken by mCallbackQueue.
-  elementData->mCallbackQueue.AppendElement(callback);
+  auto callback =
+    MakeUnique<CustomElementCallback>(aCustomElement, aType, func, elementData);
+
   if (aArgs) {
     callback->SetArgs(*aArgs);
   }
 
-  if (!elementData->mElementIsBeingCreated) {
-    CustomElementData* lastData =
-      sProcessingStack->SafeLastElement(nullptr);
-
-    // A new element queue needs to be pushed if the queue at the
-    // top of the stack is associated with another microtask level.
-    bool shouldPushElementQueue =
-      (!lastData || lastData->mAssociatedMicroTask <
-         static_cast<int32_t>(nsContentUtils::MicroTaskLevel()));
-
-    // Push a new element queue onto the processing stack when appropriate
-    // (when we enter a new microtask).
-    if (shouldPushElementQueue) {
-      // Push a sentinel value on the processing stack to mark the
-      // boundary between the element queues.
-      sProcessingStack->AppendElement((CustomElementData*) nullptr);
-    }
+  return Move(callback);
+}
 
-    sProcessingStack->AppendElement(elementData);
-    elementData->mAssociatedMicroTask =
-      static_cast<int32_t>(nsContentUtils::MicroTaskLevel());
-
-    // Add a script runner to pop and process the element queue at
-    // the top of the processing stack.
-    if (shouldPushElementQueue) {
-      // Lifecycle callbacks enqueued by user agent implementation
-      // should be invoked prior to returning control back to script.
-      // Create a script runner to process the top of the processing
-      // stack as soon as it is safe to run script.
-      nsCOMPtr<nsIRunnable> runnable =
-        NS_NewRunnableFunction(&CustomElementRegistry::ProcessTopElementQueue);
-      nsContentUtils::AddScriptRunner(runnable);
-    }
+void
+CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType aType,
+                                                Element* aCustomElement,
+                                                LifecycleCallbackArgs* aArgs,
+                                                CustomElementDefinition* aDefinition)
+{
+  auto callback =
+    CreateCustomElementCallback(aType, aCustomElement, aArgs, aDefinition);
+  if (!callback) {
+    return;
   }
+
+  DocGroup* docGroup = mWindow->GetDocGroup();
+  if (!docGroup) {
+    return;
+  }
+
+  CustomElementReactionsStack* reactionsStack =
+    docGroup->CustomElementReactionsStack();
+  reactionsStack->EnqueueCallbackReaction(this, aCustomElement, aDefinition,
+                                          Move(callback));
 }
 
 void
@@ -934,6 +865,16 @@ CustomElementReactionsStack::EnqueueUpgradeReaction(CustomElementRegistry* aRegi
 }
 
 void
+CustomElementReactionsStack::EnqueueCallbackReaction(CustomElementRegistry* aRegistry,
+                                                     Element* aElement,
+                                                     CustomElementDefinition* aDefinition,
+                                                     UniquePtr<CustomElementCallback> aCustomElementCallback)
+{
+  Enqueue(aElement, new CustomElementCallbackReaction(aRegistry, aDefinition,
+                                                      Move(aCustomElementCallback)));
+}
+
+void
 CustomElementReactionsStack::Enqueue(Element* aElement,
                                      CustomElementReaction* aReaction)
 {
@@ -1026,5 +967,14 @@ CustomElementUpgradeReaction::Invoke(Element* aElement)
   mRegistry->Upgrade(aElement, mDefinition);
 }
 
+//-----------------------------------------------------
+// CustomElementCallbackReaction
+
+/* virtual */ void
+CustomElementCallbackReaction::Invoke(Element* aElement)
+{
+  mCustomElementCallback->Call();
+}
+
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/base/CustomElementRegistry.h b/dom/base/CustomElementRegistry.h
index cb7bd67a5..33f2a95ff 100644
--- a/dom/base/CustomElementRegistry.h
+++ b/dom/base/CustomElementRegistry.h
@@ -84,23 +84,14 @@ struct CustomElementData
 
   explicit CustomElementData(nsIAtom* aType);
   CustomElementData(nsIAtom* aType, State aState);
-  // Objects in this array are transient and empty after each microtask
-  // checkpoint.
-  nsTArray<nsAutoPtr<CustomElementCallback>> mCallbackQueue;
   // Custom element type, for <button is="x-button"> or <x-button>
   // this would be x-button.
   nsCOMPtr<nsIAtom> mType;
-  // The callback that is next to be processed upon calling RunCallbackQueue.
-  int32_t mCurrentCallback;
   // Element is being created flag as described in the custom elements spec.
   bool mElementIsBeingCreated;
   // Flag to determine if the created callback has been invoked, thus it
   // determines if other callbacks can be enqueued.
   bool mCreatedCallbackInvoked;
-  // The microtask level associated with the callbacks in the callback queue,
-  // it is used to determine if a new queue needs to be pushed onto the
-  // processing stack.
-  int32_t mAssociatedMicroTask;
   // Custom element state as described in the custom element spec.
   State mState;
   // custom element reaction queue as described in the custom element spec.
@@ -109,10 +100,7 @@ struct CustomElementData
   // appended, removed, or replaced.
   // There are 3 reactions in reaction queue when doing upgrade operation,
   // e.g., create an element, insert a node.
-  AutoTArray<nsAutoPtr<CustomElementReaction>, 3> mReactionQueue;
-
-  // Empties the callback queue.
-  void RunCallbackQueue();
+  AutoTArray<UniquePtr<CustomElementReaction>, 3> mReactionQueue;
 
 private:
   virtual ~CustomElementData() {}
@@ -142,7 +130,7 @@ struct CustomElementDefinition
   JS::Heap<JSObject *> mPrototype;
 
   // The lifecycle callbacks to call for this custom element.
-  nsAutoPtr<mozilla::dom::LifecycleCallbacks> mCallbacks;
+  UniquePtr<mozilla::dom::LifecycleCallbacks> mCallbacks;
 
   // A construction stack.
   // TODO: Bug 1287348 - Implement construction stack for upgrading an element
@@ -163,10 +151,13 @@ public:
     : mRegistry(aRegistry)
     , mDefinition(aDefinition)
   {
-  };
+  }
 
   virtual ~CustomElementReaction() = default;
   virtual void Invoke(Element* aElement) = 0;
+  virtual void Traverse(nsCycleCollectionTraversalCallback& aCb) const
+  {
+  }
 
 protected:
   CustomElementRegistry* mRegistry;
@@ -186,6 +177,27 @@ private:
    virtual void Invoke(Element* aElement) override;
 };
 
+class CustomElementCallbackReaction final : public CustomElementReaction
+{
+  public:
+    CustomElementCallbackReaction(CustomElementRegistry* aRegistry,
+                                  CustomElementDefinition* aDefinition,
+                                  UniquePtr<CustomElementCallback> aCustomElementCallback)
+      : CustomElementReaction(aRegistry, aDefinition)
+      , mCustomElementCallback(Move(aCustomElementCallback))
+    {
+    }
+
+    virtual void Traverse(nsCycleCollectionTraversalCallback& aCb) const override
+    {
+      mCustomElementCallback->Traverse(aCb);
+    }
+
+  private:
+    virtual void Invoke(Element* aElement) override;
+    UniquePtr<CustomElementCallback> mCustomElementCallback;
+};
+
 // https://html.spec.whatwg.org/multipage/scripting.html#custom-element-reactions-stack
 class CustomElementReactionsStack
 {
@@ -211,6 +223,15 @@ public:
                               Element* aElement,
                               CustomElementDefinition* aDefinition);
 
+  /**
+   * Enqueue a custom element callback reaction
+   * https://html.spec.whatwg.org/multipage/scripting.html#enqueue-a-custom-element-callback-reaction
+   */
+  void EnqueueCallbackReaction(CustomElementRegistry* aRegistry,
+                               Element* aElement,
+                               CustomElementDefinition* aDefinition,
+                               UniquePtr<CustomElementCallback> aCustomElementCallback);
+
   // [CEReactions] Before executing the algorithm's steps
   // Push a new element queue onto the custom element reactions stack.
   void CreateAndPushElementQueue();
@@ -276,10 +297,6 @@ public:
   static bool IsCustomElementEnabled(JSContext* aCx = nullptr,
                                      JSObject* aObject = nullptr);
 
-  static void ProcessTopElementQueue();
-
-  static void XPCOMShutdown();
-
   explicit CustomElementRegistry(nsPIDOMWindowInner* aWindow);
 
   /**
@@ -312,6 +329,10 @@ public:
 private:
   ~CustomElementRegistry();
 
+  UniquePtr<CustomElementCallback> CreateCustomElementCallback(
+    nsIDocument::ElementCallbackType aType, Element* aCustomElement,
+    LifecycleCallbackArgs* aArgs, CustomElementDefinition* aDefinition);
+
   /**
    * Registers an unresolved custom element that is a candidate for
    * upgrade when the definition is registered via registerElement.
@@ -358,14 +379,6 @@ private:
 
   nsCOMPtr<nsPIDOMWindowInner> mWindow;
 
-  // Array representing the processing stack in the custom elements
-  // specification. The processing stack is conceptually a stack of
-  // element queues. Each queue is represented by a sequence of
-  // CustomElementData in this array, separated by nullptr that
-  // represent the boundaries of the items in the stack. The first
-  // queue in the stack is the base element queue.
-  static mozilla::Maybe<nsTArray<RefPtr<CustomElementData>>> sProcessingStack;
-
   // It is used to prevent reentrant invocations of element definition.
   bool mIsCustomDefinitionRunning;
 
diff --git a/dom/base/FragmentOrElement.cpp b/dom/base/FragmentOrElement.cpp
index 5755fb817..e341ae315 100644
--- a/dom/base/FragmentOrElement.cpp
+++ b/dom/base/FragmentOrElement.cpp
@@ -584,8 +584,10 @@ FragmentOrElement::nsDOMSlots::Traverse(nsCycleCollectionTraversalCallback &cb)
 
   if (mExtendedSlots->mCustomElementData) {
     for (uint32_t i = 0;
-         i < mExtendedSlots->mCustomElementData->mCallbackQueue.Length(); i++) {
-      mExtendedSlots->mCustomElementData->mCallbackQueue[i]->Traverse(cb);
+         i < mExtendedSlots->mCustomElementData->mReactionQueue.Length(); i++) {
+      if (mExtendedSlots->mCustomElementData->mReactionQueue[i]) {
+        mExtendedSlots->mCustomElementData->mReactionQueue[i]->Traverse(cb);
+      }
     }
   }
 
diff --git a/dom/tests/mochitest/webcomponents/test_document_register_stack.html b/dom/tests/mochitest/webcomponents/test_document_register_stack.html
index 34f108654..b1c61af11 100644
--- a/dom/tests/mochitest/webcomponents/test_document_register_stack.html
+++ b/dom/tests/mochitest/webcomponents/test_document_register_stack.html
@@ -28,7 +28,8 @@ function testChangeAttributeInCreatedCallback() {
     createdCallbackCalled = true;
     is(attributeChangedCallbackCalled, false, "Attribute changed callback should not have been called prior to setting the attribute.");
     this.setAttribute("foo", "bar");
-    is(attributeChangedCallbackCalled, false, "While element is being created, element should not be added to the current element callback queue.");
+    is(attributeChangedCallbackCalled, true, "While element is being created, element should be added to the current element callback queue.");
+    runNextTest();
   };
 
   p.attributeChangedCallback = function(name, oldValue, newValue) {
@@ -36,7 +37,6 @@ function testChangeAttributeInCreatedCallback() {
     is(attributeChangedCallbackCalled, false, "attributeChanged callback should only be called once in this tests.");
     is(newValue, "bar", "The new value should be 'bar'");
     attributeChangedCallbackCalled = true;
-    runNextTest();
   };
 
   document.registerElement("x-one", { prototype: p });