1 files changed, 259 insertions, 0 deletions
diff --git a/dom/base/CustomElementRegistry.h b/dom/base/CustomElementRegistry.h
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+++ b/dom/base/CustomElementRegistry.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_CustomElementRegistry_h
+#define mozilla_dom_CustomElementRegistry_h
+
+#include "js/TypeDecls.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/BindingDeclarations.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsWrapperCache.h"
+#include "mozilla/dom/FunctionBinding.h"
+
+class nsDocument;
+
+namespace mozilla {
+namespace dom {
+
+struct CustomElementData;
+struct ElementDefinitionOptions;
+struct LifecycleCallbacks;
+class CallbackFunction;
+class Function;
+class Promise;
+
+struct LifecycleCallbackArgs
+{
+  nsString name;
+  nsString oldValue;
+  nsString newValue;
+};
+
+class CustomElementCallback
+{
+public:
+  CustomElementCallback(Element* aThisObject,
+                        nsIDocument::ElementCallbackType aCallbackType,
+                        CallbackFunction* aCallback,
+                        CustomElementData* aOwnerData);
+  void Traverse(nsCycleCollectionTraversalCallback& aCb) const;
+  void Call();
+  void SetArgs(LifecycleCallbackArgs& aArgs)
+  {
+    MOZ_ASSERT(mType == nsIDocument::eAttributeChanged,
+               "Arguments are only used by attribute changed callback.");
+    mArgs = aArgs;
+  }
+
+private:
+  // The this value to use for invocation of the callback.
+  RefPtr<Element> mThisObject;
+  RefPtr<CallbackFunction> mCallback;
+  // The type of callback (eCreated, eAttached, etc.)
+  nsIDocument::ElementCallbackType mType;
+  // Arguments to be passed to the callback,
+  // used by the attribute changed callback.
+  LifecycleCallbackArgs mArgs;
+  // CustomElementData that contains this callback in the
+  // callback queue.
+  CustomElementData* mOwnerData;
+};
+
+// Each custom element has an associated callback queue and an element is
+// being created flag.
+struct CustomElementData
+{
+  NS_INLINE_DECL_REFCOUNTING(CustomElementData)
+
+  explicit CustomElementData(nsIAtom* aType);
+  // 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;
+
+  // Empties the callback queue.
+  void RunCallbackQueue();
+
+private:
+  virtual ~CustomElementData() {}
+};
+
+// The required information for a custom element as defined in:
+// https://html.spec.whatwg.org/multipage/scripting.html#custom-element-definition
+struct CustomElementDefinition
+{
+  CustomElementDefinition(nsIAtom* aType,
+                          nsIAtom* aLocalName,
+                          JSObject* aConstructor,
+                          JSObject* aPrototype,
+                          mozilla::dom::LifecycleCallbacks* aCallbacks,
+                          uint32_t aDocOrder);
+
+  // The type (name) for this custom element.
+  nsCOMPtr<nsIAtom> mType;
+
+  // The localname to (e.g. <button is=type> -- this would be button).
+  nsCOMPtr<nsIAtom> mLocalName;
+
+  // The custom element constructor.
+  JS::Heap<JSObject *> mConstructor;
+
+  // The prototype to use for new custom elements of this type.
+  JS::Heap<JSObject *> mPrototype;
+
+  // The lifecycle callbacks to call for this custom element.
+  nsAutoPtr<mozilla::dom::LifecycleCallbacks> mCallbacks;
+
+  // A construction stack.
+  // TODO: Bug 1287348 - Implement construction stack for upgrading an element
+
+  // The document custom element order.
+  uint32_t mDocOrder;
+};
+
+class CustomElementRegistry final : public nsISupports,
+                                    public nsWrapperCache
+{
+  // Allow nsDocument to access mCustomDefinitions and mCandidatesMap.
+  friend class ::nsDocument;
+
+public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(CustomElementRegistry)
+
+public:
+  static bool IsCustomElementEnabled(JSContext* aCx = nullptr,
+                                     JSObject* aObject = nullptr);
+  static already_AddRefed<CustomElementRegistry> Create(nsPIDOMWindowInner* aWindow);
+  static void ProcessTopElementQueue();
+
+  static void XPCOMShutdown();
+
+  /**
+   * Looking up a custom element definition.
+   * https://html.spec.whatwg.org/#look-up-a-custom-element-definition
+   */
+  CustomElementDefinition* LookupCustomElementDefinition(
+    const nsAString& aLocalName, const nsAString* aIs = nullptr) const;
+
+  /**
+   * Enqueue created callback or register upgrade candidate for
+   * newly created custom elements, possibly extending an existing type.
+   * ex. <x-button>, <button is="x-button> (type extension)
+   */
+  void SetupCustomElement(Element* aElement, const nsAString* aTypeExtension);
+
+  void EnqueueLifecycleCallback(nsIDocument::ElementCallbackType aType,
+                                Element* aCustomElement,
+                                LifecycleCallbackArgs* aArgs,
+                                CustomElementDefinition* aDefinition);
+
+  void GetCustomPrototype(nsIAtom* aAtom,
+                          JS::MutableHandle<JSObject*> aPrototype);
+
+private:
+  explicit CustomElementRegistry(nsPIDOMWindowInner* aWindow);
+  ~CustomElementRegistry();
+
+  /**
+   * Registers an unresolved custom element that is a candidate for
+   * upgrade when the definition is registered via registerElement.
+   * |aTypeName| is the name of the custom element type, if it is not
+   * provided, then element name is used. |aTypeName| should be provided
+   * when registering a custom element that extends an existing
+   * element. e.g. <button is="x-button">.
+   */
+  void RegisterUnresolvedElement(Element* aElement,
+                                 nsIAtom* aTypeName = nullptr);
+
+  void UpgradeCandidates(JSContext* aCx,
+                         nsIAtom* aKey,
+                         CustomElementDefinition* aDefinition);
+
+  typedef nsClassHashtable<nsISupportsHashKey, CustomElementDefinition>
+    DefinitionMap;
+  typedef nsClassHashtable<nsISupportsHashKey, nsTArray<nsWeakPtr>>
+    CandidateMap;
+
+  // Hashtable for custom element definitions in web components.
+  // Custom prototypes are stored in the compartment where
+  // registerElement was called.
+  DefinitionMap mCustomDefinitions;
+
+  typedef nsRefPtrHashtable<nsISupportsHashKey, Promise>
+    WhenDefinedPromiseMap;
+  WhenDefinedPromiseMap mWhenDefinedPromiseMap;
+  // The "upgrade candidates map" from the web components spec. Maps from a
+  // namespace id and local name to a list of elements to upgrade if that
+  // element is registered as a custom element.
+  CandidateMap mCandidatesMap;
+
+  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;
+
+private:
+  class MOZ_RAII AutoSetRunningFlag final {
+    public:
+      explicit AutoSetRunningFlag(CustomElementRegistry* aRegistry)
+        : mRegistry(aRegistry)
+      {
+        MOZ_ASSERT(!mRegistry->mIsCustomDefinitionRunning,
+                   "IsCustomDefinitionRunning flag should be initially false");
+        mRegistry->mIsCustomDefinitionRunning = true;
+      }
+
+      ~AutoSetRunningFlag() {
+        mRegistry->mIsCustomDefinitionRunning = false;
+      }
+
+    private:
+      CustomElementRegistry* mRegistry;
+  };
+
+public:
+  nsISupports* GetParentObject() const;
+
+  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+
+  void Define(const nsAString& aName, Function& aFunctionConstructor,
+              const ElementDefinitionOptions& aOptions, ErrorResult& aRv);
+
+  void Get(JSContext* cx, const nsAString& name,
+           JS::MutableHandle<JS::Value> aRetVal);
+
+  already_AddRefed<Promise> WhenDefined(const nsAString& aName, ErrorResult& aRv);
+};
+
+} // namespace dom
+} // namespace mozilla
+
+
+#endif // mozilla_dom_CustomElementRegistry_h