From 704318ea0a9f55cad18c4ea7f2a6805485a33d39 Mon Sep 17 00:00:00 2001
From: Gaming4JC <g4jc@hyperbola.info>
Date: Sun, 5 Jan 2020 11:21:03 -0500
Subject: Bug 1299363 - Part 5-2: Implement new upgrade steps.

Tag UXP Issue #1344
---
 dom/base/CustomElementRegistry.cpp | 182 +++++++++++++++++++++++++++++++------
 dom/base/CustomElementRegistry.h   |  30 ++++--
 2 files changed, 177 insertions(+), 35 deletions(-)

diff --git a/dom/base/CustomElementRegistry.cpp b/dom/base/CustomElementRegistry.cpp
index ce2e4b04f..e619ad599 100644
--- a/dom/base/CustomElementRegistry.cpp
+++ b/dom/base/CustomElementRegistry.cpp
@@ -19,7 +19,7 @@ namespace dom {
 void
 CustomElementCallback::Call()
 {
-  ErrorResult rv;
+  IgnoredErrorResult rv;
   switch (mType) {
     case nsIDocument::eCreated:
     {
@@ -55,10 +55,6 @@ CustomElementCallback::Call()
         mArgs.name, mArgs.oldValue, mArgs.newValue, rv);
       break;
   }
-
-  // If callbacks throw exceptions, it'll be handled and reported in
-  // Lifecycle*Callback::Call function.
-  rv.SuppressException();
 }
 
 void
@@ -82,6 +78,38 @@ CustomElementCallback::CustomElementCallback(Element* aThisObject,
 {
 }
 
+//-----------------------------------------------------
+// CustomElementConstructor
+
+already_AddRefed<Element>
+CustomElementConstructor::Construct(const char* aExecutionReason,
+                                    ErrorResult& aRv)
+{
+  CallSetup s(this, aRv, aExecutionReason,
+              CallbackFunction::eRethrowExceptions);
+
+  JSContext* cx = s.GetContext();
+  if (!cx) {
+    MOZ_ASSERT(aRv.Failed());
+    return nullptr;
+  }
+
+  JS::Rooted<JSObject*> result(cx);
+  JS::Rooted<JS::Value> constructor(cx, JS::ObjectValue(*mCallback));
+  if (!JS::Construct(cx, constructor, JS::HandleValueArray::empty(), &result)) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+
+  RefPtr<Element> element;
+  if (NS_FAILED(UNWRAP_OBJECT(Element, &result, element))) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+
+  return element.forget();
+}
+
 //-----------------------------------------------------
 // CustomElementData
 
@@ -101,6 +129,33 @@ CustomElementData::CustomElementData(nsIAtom* aType, State aState)
 //-----------------------------------------------------
 // CustomElementRegistry
 
+namespace {
+
+class MOZ_RAII AutoConstructionStackEntry final
+{
+public:
+  AutoConstructionStackEntry(nsTArray<RefPtr<nsGenericHTMLElement>>& aStack,
+                             nsGenericHTMLElement* aElement)
+    : mStack(aStack)
+  {
+    mIndex = mStack.Length();
+    mStack.AppendElement(aElement);
+  }
+
+  ~AutoConstructionStackEntry()
+  {
+    MOZ_ASSERT(mIndex == mStack.Length() - 1,
+               "Removed element should be the last element");
+    mStack.RemoveElementAt(mIndex);
+  }
+
+private:
+  nsTArray<RefPtr<nsGenericHTMLElement>>& mStack;
+  uint32_t mIndex;
+};
+
+} // namespace anonymous
+
 // Only needed for refcounted objects.
 NS_IMPL_CYCLE_COLLECTION_CLASS(CustomElementRegistry)
 
@@ -139,6 +194,10 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CustomElementRegistry)
         "mCustomDefinitions->mCallbacks->mDetachedCallback");
       cb.NoteXPCOMChild(callbacks->mDetachedCallback.Value());
     }
+
+    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb,
+      "mCustomDefinitions->mConstructor");
+    cb.NoteXPCOMChild(iter.UserData()->mConstructor);
   }
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWhenDefinedPromiseMap)
@@ -147,9 +206,6 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CustomElementRegistry)
   for (auto iter = tmp->mCustomDefinitions.Iter(); !iter.Done(); iter.Next()) {
-    aCallbacks.Trace(&iter.UserData()->mConstructor,
-                     "mCustomDefinitions constructor",
-                     aClosure);
     aCallbacks.Trace(&iter.UserData()->mPrototype,
                      "mCustomDefinitions prototype",
                      aClosure);
@@ -418,6 +474,7 @@ CustomElementRegistry::UpgradeCandidates(nsIAtom* aKey,
     return;
   }
 
+  // TODO: Bug 1326028 - Upgrade custom element in shadow-including tree order
   nsAutoPtr<nsTArray<nsWeakPtr>> candidates;
   mCandidatesMap.RemoveAndForget(aKey, candidates);
   if (candidates) {
@@ -696,7 +753,7 @@ CustomElementRegistry::Define(const nsAString& aName,
   CustomElementDefinition* definition =
     new CustomElementDefinition(nameAtom,
                                 localNameAtom,
-                                constructor,
+                                &aFunctionConstructor,
                                 constructorPrototype,
                                 callbacks,
                                 0 /* TODO dependent on HTML imports. Bug 877072 */);
@@ -717,7 +774,6 @@ CustomElementRegistry::Define(const nsAString& aName,
   /**
    * 13. 14. 15. Upgrade candidates
    */
-  // TODO: Bug 1299363 - Implement custom element v1 upgrade algorithm
   UpgradeCandidates(nameAtom, definition, aRv);
 
   /**
@@ -748,7 +804,7 @@ CustomElementRegistry::Get(JSContext* aCx, const nsAString& aName,
     return;
   }
 
-  aRetVal.setObject(*data->mConstructor);
+  aRetVal.setObjectOrNull(data->mConstructor->Callable());
   return;
 }
 
@@ -782,23 +838,67 @@ CustomElementRegistry::WhenDefined(const nsAString& aName, ErrorResult& aRv)
   return promise.forget();
 }
 
+namespace {
+
+static void
+DoUpgrade(Element* aElement,
+          CustomElementConstructor* aConstructor,
+          ErrorResult& aRv)
+{
+  // Rethrow the exception since it might actually throw the exception from the
+  // upgrade steps back out to the caller of document.createElement.
+  RefPtr<Element> constructResult =
+    aConstructor->Construct("Custom Element Upgrade", aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  if (constructResult.get() != aElement) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+}
+
+} // anonymous namespace
+
+// https://html.spec.whatwg.org/multipage/scripting.html#upgrades
 void
 CustomElementRegistry::Upgrade(Element* aElement,
-                               CustomElementDefinition* aDefinition)
+                               CustomElementDefinition* aDefinition,
+                               ErrorResult& aRv)
 {
-  // TODO: This function will be replaced to v1 upgrade in bug 1299363
   aElement->RemoveStates(NS_EVENT_STATE_UNRESOLVED);
 
-  // Make sure that the element name matches the name in the definition.
-  // (e.g. a definition for x-button extending button should match
-  // <button is="x-button"> but not <x-button>.
-  if (aElement->NodeInfo()->NameAtom() != aDefinition->mLocalName) {
-    //Skip over this element because definition does not apply.
+  RefPtr<CustomElementData> data = aElement->GetCustomElementData();
+  MOZ_ASSERT(data, "CustomElementData should exist");
+
+  // Step 1 and step 2.
+  if (data->mState == CustomElementData::State::eCustom ||
+      data->mState == CustomElementData::State::eFailed) {
+    return;
+  }
+
+  // Step 3 and Step 4.
+  // TODO: Bug 1334051 - Implement list of observed attributes for custom elements' attributeChanged callbacks
+  // TODO: Bug 1334043 - Implement connected lifecycle callbacks for custom elements
+
+  // Step 5.
+  AutoConstructionStackEntry acs(aDefinition->mConstructionStack,
+                                 nsGenericHTMLElement::FromContent(aElement));
+
+  // Step 6 and step 7.
+  DoUpgrade(aElement, aDefinition->mConstructor, aRv);
+  if (aRv.Failed()) {
+    data->mState = CustomElementData::State::eFailed;
+    // Empty element's custom element reaction queue.
+    data->mReactionQueue.Clear();
     return;
   }
 
-  MOZ_ASSERT(aElement->IsHTMLElement(aDefinition->mLocalName));
+  // Step 8.
+  data->mState = CustomElementData::State::eCustom;
 
+  // This is for old spec.
   EnqueueLifecycleCallback(nsIDocument::eCreated, aElement, nullptr, aDefinition);
 }
 
@@ -824,7 +924,13 @@ CustomElementReactionsStack::PopAndInvokeElementQueue()
   ElementQueue* elementQueue = mReactionsStack.ElementAt(lastIndex).get();
   // Check element queue size in order to reduce function call overhead.
   if (!elementQueue->IsEmpty()) {
-    InvokeReactions(elementQueue);
+    // It is still not clear what error reporting will look like in custom
+    // element, see https://github.com/w3c/webcomponents/issues/635.
+    // We usually report the error to entry global in gecko, so just follow the
+    // same behavior here.
+    nsIGlobalObject* global = GetEntryGlobal();
+    MOZ_ASSERT(global, "Should always have a entry global here!");
+    InvokeReactions(elementQueue, global);
   }
 
   // InvokeReactions() might create other custom element reactions, but those
@@ -887,13 +993,24 @@ CustomElementReactionsStack::InvokeBackupQueue()
 {
   // Check backup queue size in order to reduce function call overhead.
   if (!mBackupQueue.IsEmpty()) {
-    InvokeReactions(&mBackupQueue);
+    // Upgrade reactions won't be scheduled in backup queue and the exception of
+    // callback reactions will be automatically reported in CallSetup.
+    // If the reactions are invoked from backup queue (in microtask check point),
+    // we don't need to pass global object for error reporting.
+    InvokeReactions(&mBackupQueue, nullptr);
   }
 }
 
 void
-CustomElementReactionsStack::InvokeReactions(ElementQueue* aElementQueue)
+CustomElementReactionsStack::InvokeReactions(ElementQueue* aElementQueue,
+                                             nsIGlobalObject* aGlobal)
 {
+  // This is used for error reporting.
+  Maybe<AutoEntryScript> aes;
+  if (aGlobal) {
+    aes.emplace(aGlobal, "custom elements reaction invocation");
+  }
+
   // Note: It's possible to re-enter this method.
   for (uint32_t i = 0; i < aElementQueue->Length(); ++i) {
     nsCOMPtr<Element> element = do_QueryReferent(aElementQueue->ElementAt(i));
@@ -911,7 +1028,16 @@ CustomElementReactionsStack::InvokeReactions(ElementQueue* aElementQueue)
       // this funciton. The entry will be removed when bug 1379573 is landed.
       auto reaction(Move(reactions.ElementAt(j)));
       if (reaction) {
-        reaction->Invoke(element);
+        ErrorResult rv;
+        reaction->Invoke(element, rv);
+        if (aes) {
+          JSContext* cx = aes->cx();
+          if (rv.MaybeSetPendingException(cx)) {
+            aes->ReportException();
+          }
+          MOZ_ASSERT(!JS_IsExceptionPending(cx));
+        }
+        MOZ_ASSERT(!rv.Failed());
       }
     }
     reactions.Clear();
@@ -924,13 +1050,13 @@ CustomElementReactionsStack::InvokeReactions(ElementQueue* aElementQueue)
 
 CustomElementDefinition::CustomElementDefinition(nsIAtom* aType,
                                                  nsIAtom* aLocalName,
-                                                 JSObject* aConstructor,
+                                                 Function* aConstructor,
                                                  JSObject* aPrototype,
                                                  LifecycleCallbacks* aCallbacks,
                                                  uint32_t aDocOrder)
   : mType(aType),
     mLocalName(aLocalName),
-    mConstructor(aConstructor),
+    mConstructor(new CustomElementConstructor(aConstructor)),
     mPrototype(aPrototype),
     mCallbacks(aCallbacks),
     mDocOrder(aDocOrder)
@@ -941,16 +1067,16 @@ CustomElementDefinition::CustomElementDefinition(nsIAtom* aType,
 // CustomElementUpgradeReaction
 
 /* virtual */ void
-CustomElementUpgradeReaction::Invoke(Element* aElement)
+CustomElementUpgradeReaction::Invoke(Element* aElement, ErrorResult& aRv)
 {
-  mRegistry->Upgrade(aElement, mDefinition);
+  mRegistry->Upgrade(aElement, mDefinition, aRv);
 }
 
 //-----------------------------------------------------
 // CustomElementCallbackReaction
 
 /* virtual */ void
-CustomElementCallbackReaction::Invoke(Element* aElement)
+CustomElementCallbackReaction::Invoke(Element* aElement, ErrorResult& aRv)
 {
   mCustomElementCallback->Call();
 }
diff --git a/dom/base/CustomElementRegistry.h b/dom/base/CustomElementRegistry.h
index 620492cbb..c45f3f70c 100644
--- a/dom/base/CustomElementRegistry.h
+++ b/dom/base/CustomElementRegistry.h
@@ -66,6 +66,18 @@ private:
   CustomElementData* mOwnerData;
 };
 
+class CustomElementConstructor final : public CallbackFunction
+{
+public:
+  explicit CustomElementConstructor(CallbackFunction* aOther)
+    : CallbackFunction(aOther)
+  {
+    MOZ_ASSERT(JS::IsConstructor(mCallback));
+  }
+
+  already_AddRefed<Element> Construct(const char* aExecutionReason, ErrorResult& aRv);
+};
+
 // Each custom element has an associated callback queue and an element is
 // being created flag.
 struct CustomElementData
@@ -114,7 +126,7 @@ struct CustomElementDefinition
 {
   CustomElementDefinition(nsIAtom* aType,
                           nsIAtom* aLocalName,
-                          JSObject* aConstructor,
+                          Function* aConstructor,
                           JSObject* aPrototype,
                           mozilla::dom::LifecycleCallbacks* aCallbacks,
                           uint32_t aDocOrder);
@@ -126,7 +138,7 @@ struct CustomElementDefinition
   nsCOMPtr<nsIAtom> mLocalName;
 
   // The custom element constructor.
-  JS::Heap<JSObject *> mConstructor;
+  RefPtr<CustomElementConstructor> mConstructor;
 
   // The prototype to use for new custom elements of this type.
   JS::Heap<JSObject *> mPrototype;
@@ -156,7 +168,7 @@ public:
   }
 
   virtual ~CustomElementReaction() = default;
-  virtual void Invoke(Element* aElement) = 0;
+  virtual void Invoke(Element* aElement, ErrorResult& aRv) = 0;
   virtual void Traverse(nsCycleCollectionTraversalCallback& aCb) const
   {
   }
@@ -176,7 +188,7 @@ public:
   }
 
 private:
-   virtual void Invoke(Element* aElement) override;
+   virtual void Invoke(Element* aElement, ErrorResult& aRv) override;
 };
 
 class CustomElementCallbackReaction final : public CustomElementReaction
@@ -196,7 +208,7 @@ class CustomElementCallbackReaction final : public CustomElementReaction
     }
 
   private:
-    virtual void Invoke(Element* aElement) override;
+    virtual void Invoke(Element* aElement, ErrorResult& aRv) override;
     UniquePtr<CustomElementCallback> mCustomElementCallback;
 };
 
@@ -258,7 +270,7 @@ private:
    * Invoke custom element reactions
    * https://html.spec.whatwg.org/multipage/scripting.html#invoke-custom-element-reactions
    */
-  void InvokeReactions(ElementQueue* aElementQueue);
+  void InvokeReactions(ElementQueue* aElementQueue, nsIGlobalObject* aGlobal);
 
   void Enqueue(Element* aElement, CustomElementReaction* aReaction);
 
@@ -326,7 +338,11 @@ public:
   void GetCustomPrototype(nsIAtom* aAtom,
                           JS::MutableHandle<JSObject*> aPrototype);
 
-  void Upgrade(Element* aElement, CustomElementDefinition* aDefinition);
+  /**
+   * Upgrade an element.
+   * https://html.spec.whatwg.org/multipage/scripting.html#upgrades
+   */
+  void Upgrade(Element* aElement, CustomElementDefinition* aDefinition, ErrorResult& aRv);
 
 private:
   ~CustomElementRegistry();
-- 
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