Bug 1552313 - Implement disableShadow; r=smaug,edgar

Differential Revision: https://phabricator.services.mozilla.com/D52157

--HG--
extra : moz-landing-system : lando

dom/base/CustomElementRegistry.cpp

@@ -839,6 +839,7 @@ void CustomElementRegistry::Define(
   nsTArray<RefPtr<nsAtom>> observedAttributes;
   AutoTArray<RefPtr<nsAtom>, 2> disabledFeatures;
   bool disableInternals = false;
+  bool disableShadow = false;
   {  // Set mIsCustomDefinitionRunning.
     /**
      * 9. Set this CustomElementRegistry's element definition is running flag.
@@ -923,6 +924,11 @@ void CustomElementRegistry::Define(
       //       "internals".
       disableInternals = disabledFeatures.Contains(
           static_cast<nsStaticAtom*>(nsGkAtoms::internals));
+
+      // 14.10. Set disableShadow to true if disabledFeaturesSequence contains
+      //        "shadow".
+      disableShadow = disabledFeatures.Contains(
+          static_cast<nsStaticAtom*>(nsGkAtoms::shadow));
     }
   }  // Unset mIsCustomDefinitionRunning
 
@@ -946,7 +952,7 @@ void CustomElementRegistry::Define(
   RefPtr<CustomElementDefinition> definition = new CustomElementDefinition(
       nameAtom, localNameAtom, nameSpaceID, &aFunctionConstructor,
       std::move(observedAttributes), std::move(callbacksHolder),
-      disableInternals);
+      disableInternals, disableShadow);
 
   CustomElementDefinition* def = definition.get();
   mCustomDefinitions.Put(nameAtom, definition.forget());
@@ -1083,8 +1089,19 @@ already_AddRefed<Promise> CustomElementRegistry::WhenDefined(
 namespace {
 
 MOZ_CAN_RUN_SCRIPT
-static void DoUpgrade(Element* aElement, CustomElementConstructor* aConstructor,
+static void DoUpgrade(Element* aElement, CustomElementDefinition* aDefinition,
+                      CustomElementConstructor* aConstructor,
                       ErrorResult& aRv) {
+  if (aDefinition->mDisableShadow && aElement->GetShadowRoot()) {
+    aRv.ThrowDOMException(
+        NS_ERROR_DOM_NOT_SUPPORTED_ERR,
+        nsPrintfCString(
+            "Custom element upgrade to '%s' is disabled due to shadow root "
+            "already exists",
+            NS_ConvertUTF16toUTF8(aDefinition->mType->GetUTF16String()).get()));
+    return;
+  }
+
   JS::Rooted<JS::Value> constructResult(RootingCx());
   // Rethrow the exception since it might actually throw the exception from the
   // upgrade steps back out to the caller of document.createElement.
@@ -1155,7 +1172,8 @@ void CustomElementRegistry::Upgrade(Element* aElement,
   AutoConstructionStackEntry acs(aDefinition->mConstructionStack, aElement);
 
   // Step 6 and step 7.
-  DoUpgrade(aElement, MOZ_KnownLive(aDefinition->mConstructor), aRv);
+  DoUpgrade(aElement, aDefinition, MOZ_KnownLive(aDefinition->mConstructor),
+            aRv);
   if (aRv.Failed()) {
     data->mState = CustomElementData::State::eFailed;
     // Empty element's custom element reaction queue.
@@ -1436,14 +1454,16 @@ CustomElementDefinition::CustomElementDefinition(
     nsAtom* aType, nsAtom* aLocalName, int32_t aNamespaceID,
     CustomElementConstructor* aConstructor,
     nsTArray<RefPtr<nsAtom>>&& aObservedAttributes,
-    UniquePtr<LifecycleCallbacks>&& aCallbacks, bool aDisableInternals)
+    UniquePtr<LifecycleCallbacks>&& aCallbacks, bool aDisableInternals,
+    bool aDisableShadow)
     : mType(aType),
       mLocalName(aLocalName),
       mNamespaceID(aNamespaceID),
       mConstructor(aConstructor),
       mObservedAttributes(std::move(aObservedAttributes)),
       mCallbacks(std::move(aCallbacks)),
-      mDisableInternals(aDisableInternals) {}
+      mDisableInternals(aDisableInternals),
+      mDisableShadow(aDisableShadow) {}
 
 }  // namespace dom
 }  // namespace mozilla

dom/base/CustomElementRegistry.h

@@ -138,7 +138,7 @@ struct CustomElementDefinition {
                           CustomElementConstructor* aConstructor,
                           nsTArray<RefPtr<nsAtom>>&& aObservedAttributes,
                           UniquePtr<LifecycleCallbacks>&& aCallbacks,
-                          bool aDisableInternals);
+                          bool aDisableInternals, bool aDisableShadow);
 
   // The type (name) for this custom element, for <button is="x-foo"> or <x-foo>
   // this would be x-foo.
@@ -162,6 +162,9 @@ struct CustomElementDefinition {
   // Determine whether to allow to attachInternals() for this custom element.
   bool mDisableInternals = false;
 
+  // Determine whether to allow to attachShadow() for this custom element.
+  bool mDisableShadow = false;
+
   // A construction stack. Use nullptr to represent an "already constructed
   // marker".
   nsTArray<RefPtr<Element>> mConstructionStack;

dom/base/Element.cpp

@@ -977,8 +977,8 @@ bool Element::CanAttachShadowDOM() const {
    *  return false.
    */
   nsAtom* nameAtom = NodeInfo()->NameAtom();
-  if (!(nsContentUtils::IsCustomElementName(nameAtom,
-                                            NodeInfo()->NamespaceID()) ||
+  uint32_t namespaceID = NodeInfo()->NamespaceID();
+  if (!(nsContentUtils::IsCustomElementName(nameAtom, namespaceID) ||
         nameAtom == nsGkAtoms::article || nameAtom == nsGkAtoms::aside ||
         nameAtom == nsGkAtoms::blockquote || nameAtom == nsGkAtoms::body ||
         nameAtom == nsGkAtoms::div || nameAtom == nsGkAtoms::footer ||
@@ -991,6 +991,30 @@ bool Element::CanAttachShadowDOM() const {
     return false;
   }
 
+  /**
+   * 3. If context object’s local name is a valid custom element name, or
+   *    context object’s is value is not null, then:
+   *    If definition is not null and definition’s disable shadow is true, then
+   *    return false.
+   */
+  // It will always have CustomElementData when the element is a valid custom
+  // element or has is value.
+  CustomElementData* ceData = GetCustomElementData();
+  if (StaticPrefs::dom_webcomponents_elementInternals_enabled() && ceData) {
+    CustomElementDefinition* definition = ceData->GetCustomElementDefinition();
+    // If the definition is null, the element possible hasn't yet upgraded.
+    // Fallback to use LookupCustomElementDefinition to find its definition.
+    if (!definition) {
+      definition = nsContentUtils::LookupCustomElementDefinition(
+          NodeInfo()->GetDocument(), nameAtom, namespaceID,
+          ceData->GetCustomElementType());
+    }
+
+    if (definition && definition->mDisableShadow) {
+      return false;
+    }
+  }
+
   return true;
 }
 
@@ -1009,11 +1033,11 @@ already_AddRefed<ShadowRoot> Element::AttachShadow(const ShadowRootInit& aInit,
   }
 
   /**
-   * 3. If context object is a shadow host, then throw
-   *    an "InvalidStateError" DOMException.
+   * 4. If context object is a shadow host, then throw
+   *    an "NotSupportedError" DOMException.
    */
   if (GetShadowRoot()) {
-    aError.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    aError.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return nullptr;
   }
 

testing/web-platform/meta/shadow-dom/__dir__.ini

@@ -0,0 +1 @@
+prefs: [dom.webcomponents.elementInternals.enabled:true]

testing/web-platform/tests/shadow-dom/Element-interface-attachShadow-custom-element.html

@@ -77,7 +77,7 @@
 
 test(() => {
   class CapitalShadowDisabledElement extends HTMLElement {
-    static get disabledFeatures() { return ['shadow']; }
+    static get disabledFeatures() { return ['SHADOW']; }
   }
 
   customElements.define('capital-shadow-disabled-element', CapitalShadowDisabledElement);

xpcom/ds/StaticAtoms.py

@@ -1088,6 +1088,7 @@
     Atom("seltype", "seltype"),
     Atom("setcookie", "set-cookie"),
     Atom("setter", "setter"),
+    Atom("shadow", "shadow"),
     Atom("shape", "shape"),
     Atom("show", "show"),
     Atom("showcaret", "showcaret"),